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asqui
July 16th 03, 02:57 PM
In the footage of Beloki's spectacular crash it can be seen that Armstrong
briefly locks up his rear wheel as Beloki crashes. I thought on a decent
surface the best way to stop was front brake only? I guess that was feasible
with the Weinmann brakes on my Eddy Meckx but these Tektro cantilevers leave
some braking performance to be desired :(. Anyway, obviously on a descent
like that you'll want to use both to distribute the rim heating evenly, but
why did Lance lock up the rear? In the emergency situation shouldn't he have
been using the front brake exclusively -- exactly for the reason of avoiding
a rear wheel skid?

(I will agree that front brake only is a little "eggs in one basket" because
if you wash out the front you're pretty much gone, but I'm arguing based on
the "front brake only" rule I've heard time and time again.)

Dani

rayneman
July 16th 03, 03:39 PM
Dani, try this... Go out and find a big hill, get going really fast and
grab your front brake, hard as you can like you would in an emergency
situation. When you get out of the hospital, write back and let us know
how it works.
Thanks,
Ray

asqui wrote:
> In the footage of Beloki's spectacular crash it can be seen that Armstrong
> briefly locks up his rear wheel as Beloki crashes. I thought on a decent
> surface the best way to stop was front brake only? I guess that was feasible
> with the Weinmann brakes on my Eddy Meckx but these Tektro cantilevers leave
> some braking performance to be desired :(. Anyway, obviously on a descent
> like that you'll want to use both to distribute the rim heating evenly, but
> why did Lance lock up the rear? In the emergency situation shouldn't he have
> been using the front brake exclusively -- exactly for the reason of avoiding
> a rear wheel skid?
>
> (I will agree that front brake only is a little "eggs in one basket" because
> if you wash out the front you're pretty much gone, but I'm arguing based on
> the "front brake only" rule I've heard time and time again.)
>
> Dani
>
>

Callistus Valerius
July 16th 03, 04:03 PM
> Dani, try this... Go out and find a big hill, get going really fast and
> grab your front brake, hard as you can like you would in an emergency
> situation. When you get out of the hospital, write back and let us know
> how it works.
> Thanks,
> Ray
>

what foolishness, everyone knows it's both brakes.

asqui
July 16th 03, 04:35 PM
Callistus Valerius wrote:
>> Dani, try this... Go out and find a big hill, get going really fast
>> and grab your front brake, hard as you can like you would in an
>> emergency situation. When you get out of the hospital, write back
>> and let us know how it works.
>> Thanks,
>> Ray
>>
>
> what foolishness, everyone knows it's both brakes.

The argument I have heard is thus:

Since the center of gravity of the human-bike system is higher than the
wheel-road interface (which provides the braking force) the human-bike
system has the tendency to pitch forward with braking, causing weight
transfer to the front wheel.
Hence the theoretical scenario for maximal braking would be that the braking
is sufficient to transfer all weight to the front wheel, leaving the rear
wheel with zero force on the ground. At this point any increase in braking
force of the front wheel would cause the rear wheel to lose contact with the
ground, and braking on the rear wheel would cause the it to skid and
increase the chances of the rider losing control.

This assumes that the front wheel has sufficient friction with the road (in
order to not skid) and brake blocks (in order to receive the necessary
braking force).

As for the experiment, I've already carried it out -- steep downhill, amber
light, car in front stops. I managed to stop about a meter behind said car,
with my rear wheel off the ground and trying to overtake me. I think that
was because I was out of the saddle and didn't sit down on it properly as I
was braking. Ideally I would have sat down and shifted my weight back to
keep the rear wheel on the ground and increase my stability.

What do you think?

Dani

Daniel Connelly
July 16th 03, 04:56 PM
asqui wrote:
> Callistus Valerius wrote:
> The argument I have heard is thus:
>
> Since the center of gravity of the human-bike system is higher than the
> wheel-road interface (which provides the braking force) the human-bike
> system has the tendency to pitch forward with braking, causing weight
> transfer to the front wheel.
> Hence the theoretical scenario for maximal braking would be that the braking
> is sufficient to transfer all weight to the front wheel, leaving the rear
> wheel with zero force on the ground. At this point any increase in braking
> force of the front wheel would cause the rear wheel to lose contact with the
> ground, and braking on the rear wheel would cause the it to skid and
> increase the chances of the rider losing control.
>
> This assumes that the front wheel has sufficient friction with the road (in
> order to not skid) and brake blocks (in order to receive the necessary
> braking force).
>
> As for the experiment, I've already carried it out -- steep downhill, amber
> light, car in front stops. I managed to stop about a meter behind said car,
> with my rear wheel off the ground and trying to overtake me. I think that
> was because I was out of the saddle and didn't sit down on it properly as I
> was braking. Ideally I would have sat down and shifted my weight back to
> keep the rear wheel on the ground and increase my stability.
>
> What do you think?

In real world conditions, uncertainty in the current state of the
system, plus time-variation in the conditions, means it's not possible
to brake at the theoretical limit. This makes it prudent to
apply rear braking force, as well. As the deceleration increases, the
normal force at the rear tire/road contact decreases, decreasing the braking
force relative to what it would be if only the front brake was used.
OTOH, if all force is applied to the front brake, an increase in the
normal force at the front tire due to a momentary increase in the rate
of deceleration will have maximum positive feedback as braking force
is then increased. Positive feedback is destabilizing.

Result: hospitalization.

Dan

asqui
July 17th 03, 02:11 AM
rayneman wrote:
> Dani, try this... Go out and find a big hill, get going really fast
> and
> grab your front brake, hard as you can like you would in an emergency
> situation. When you get out of the hospital, write back and let us
> know
> how it works.
> Thanks,
> Ray

If I was going to indiscriminately squeeze as hard as I possibly could on a
single lever, I don't think it would make any difference whether I skid the
front, skid the rear uncontrollably and slide, or possibly even fail to
brace my hands against the bars and fly over them before developing enough
braking force to skid the front wheel.

I was talking about effective braking technique, not how to hurt yourself by
panicking in an emergency and doing something rash.

The rec.bicycles.* faq (http://draco.acs.uci.edu/rbfaq/FAQ/9.17.html) and
Sheldon Brown (http://sheldonbrown.com/brakturn.html) are the most likely
candidates for where I heard about the front-brake-only technique. I hope
you will agree that they are both reputable sources and present the solid
justification for this technique.

Dani

S. Anderson
July 17th 03, 03:36 AM
"asqui" > wrote in message
...
> rayneman wrote:
>
> If I was going to indiscriminately squeeze as hard as I possibly could on
a
> single lever, I don't think it would make any difference whether I skid
the
> front, skid the rear uncontrollably and slide, or possibly even fail to
> brace my hands against the bars and fly over them before developing enough
> braking force to skid the front wheel.
>
> I was talking about effective braking technique, not how to hurt yourself
by
> panicking in an emergency and doing something rash.
>
> The rec.bicycles.* faq (http://draco.acs.uci.edu/rbfaq/FAQ/9.17.html) and
> Sheldon Brown (http://sheldonbrown.com/brakturn.html) are the most likely
> candidates for where I heard about the front-brake-only technique. I hope
> you will agree that they are both reputable sources and present the solid
> justification for this technique.
>
> Dani
>

Both the FAQ and Mr. Brown are correct and I don't think they advocate
front-brake only for max braking. Max braking is a slippery ideal. Even
with full concentration it's a tricky thing. Put the purple mist or sheer
panic into the mix and it's nearly impossible to achieve consistently. Max
braking does occur when the rear wheel is leaving the ground, effectively
making the rear brake useless. But it's a tricky thing to accomplish. So
unless the rear wheel is off the ground, the rear brake is making SOME
contribution, however very little it may be. It's a sliding scale, front
versus rear brake, depending on how much deceleration is occuring and how
much weight is on the rear wheel. In a situation like Beloki's crash, these
things can easily overwhelm even the best riders. We're talking about a guy
who makes his professional living climbing and descending mountains..I'm
sure he's well aware of braking techniques and maybe he was simply in a
situation that was impossible. There may have been just too much sensory
input to decode and he just made a mistake.

Incidentally, I hit the racetrack every now and again with my motorcycle and
I NEVER touch the rear brake when at the track. However, if you watch the
good guys, you can see them sliding the rear tire into corners using the
rear brake and engine braking. These guys are able to decode the input from
the bike to do those things. I'm simply overwhelmed with all the stuff
going on and cannot do the stuff they do. So your idea of front-brake only
may be analogous to my motorcycle situation..if you can't reliably operate
the rear brake during max braking so that the rear wheel doesn't skid,
you're probably better off using the front only.

Cheers,

Scott..

warren
July 17th 03, 04:02 AM
In article >, asqui
> wrote:

> warren wrote:
> > I think you should worry less about invalid "arguments" and spend the
> > time practicing with both brakes and keeping your weight farther back
> > under heavy braking. Don't you think that having two tires making
> > contact/friction with the ground would work better?
> >
> > -WG
>
> So yeah... now that I found out where I read this invalid argument perhaps
> you would like to consult the rec.bicycles.* faq around here:
> http://draco.acs.uci.edu/rbfaq/FAQ/9.17.html
> Eating one's hat is optional.

Look dude, 700+ criteriums and riding up and down the 15mph switchbacks
here in the Sierra foothills have taught me plenty about braking. It's
true that more braking force is used on the front wheel but you were
talking about putting none on the rear wheel, which is dumb.

Stay out of my way in the turns.

-WG

S. Anderson
July 17th 03, 05:12 AM
"warren" > wrote in message
...
> In article >, asqui
> > wrote:
>
>
> Look dude, 700+ criteriums and riding up and down the 15mph switchbacks
> here in the Sierra foothills have taught me plenty about braking. It's
> true that more braking force is used on the front wheel but you were
> talking about putting none on the rear wheel, which is dumb.
>
> Stay out of my way in the turns.
>
> -WG

700+ criteriums?? How many years have you been racing?? That's a bit of
practice to be sure! And you're right. Braking is a dynamic condition..the
amount of traction on either wheel is going to be variable depending on a
number of factors and save for that amazingly fine line where the rear wheel
begins to lift off, the rear wheel does contribute some braking.

Cheers,

Scott..

Zelda
July 17th 03, 02:53 PM
Since you compare bicycles to motorcycles, I have a different
question:

I used to ride motorcycles, and tried amateur roadracing for a couple
of years. Last year, when I bought my first-ever good quality road
bicycle, I asked the staff at the bike shop if you use countersteering
to go around fast corners on a bicycle, as you do on a motorcycle
(pushing the handlebar away from you). They didn't know what I was
talking about.

So, do you use countersteering on a road bicycle?

Thanks,
Zelda

"S. Anderson" > wrote in message >...
> (snip)
> Incidentally, I hit the racetrack every now and again with my motorcycle and
> I NEVER touch the rear brake when at the track. However, if you watch the
> good guys, you can see them sliding the rear tire into corners using the
> rear brake and engine braking. These guys are able to decode the input from
> the bike to do those things. I'm simply overwhelmed with all the stuff
> going on and cannot do the stuff they do. So your idea of front-brake only
> may be analogous to my motorcycle situation..if you can't reliably operate
> the rear brake during max braking so that the rear wheel doesn't skid,
> you're probably better off using the front only.
>
> Cheers,
>
> Scott..

warren
July 17th 03, 04:29 PM
In article >, asqui
> wrote:

> Andrew Lee wrote:
> > "asqui" > wrote
> >
> >> warren wrote:
> >>> I think you should worry less about invalid "arguments" and spend
> >>> the time practicing with both brakes and keeping your weight
> >>> farther back under heavy braking. Don't you think that having two
> >>> tires making contact/friction with the ground would work better?
> >>>
> >>> -WG
> >>
> >> So yeah... now that I found out where I read this invalid argument
> >> perhaps you would like to consult the rec.bicycles.* faq around here:
> >> http://draco.acs.uci.edu/rbfaq/FAQ/9.17.html
> >> Eating one's hat is optional.
> >
> > Try reading this: http://draco.acs.uci.edu/rbfaq/FAQ/9.15.html
> >
> > This has more information about braking in the context of corners...
>
> Sorry, perhaps I wasn't clear in my original post. I was referring to
> emergency braking on a good surface in a straight line. Armstrong was
> braking in a straight line as he came past the outside of Beloki. This
> section of the faq states once more that front brake only is the quickest
> way to decelerate as long as you're not banked in the middle of a turn.

Then it's wrong. Think about my question again...

"Don't you think that having two tires making contact/friction with the
ground (with the brakes applied) would work better than one?"

Why don't you go out and test your theory and that FAQ statement and
get back to us? Make sure to bring your hat.

-WG

Mike S.
July 17th 03, 06:07 PM
"asqui" > wrote in message
...
> Andrew Lee wrote:
> > "asqui" > wrote
> >
> >> warren wrote:
> >>> I think you should worry less about invalid "arguments" and spend
> >>> the time practicing with both brakes and keeping your weight
> >>> farther back under heavy braking. Don't you think that having two
> >>> tires making contact/friction with the ground would work better?
> >>>
> >>> -WG
> >>
> >> So yeah... now that I found out where I read this invalid argument
> >> perhaps you would like to consult the rec.bicycles.* faq around here:
> >> http://draco.acs.uci.edu/rbfaq/FAQ/9.17.html
> >> Eating one's hat is optional.
> >
> > Try reading this: http://draco.acs.uci.edu/rbfaq/FAQ/9.15.html
> >
> > This has more information about braking in the context of corners...
>
> Sorry, perhaps I wasn't clear in my original post. I was referring to
> emergency braking on a good surface in a straight line. Armstrong was
> braking in a straight line as he came past the outside of Beloki. This
> section of the faq states once more that front brake only is the quickest
> way to decelerate as long as you're not banked in the middle of a turn.
>
>
And using the front brake only is also the easiest way to end up over the
bars and on the ground! If you aren't careful, the front brake has more
than enough power to dump you on your arse.

Mike

Mike S.
July 17th 03, 06:11 PM
"Zelda" > wrote in message
om...
> Since you compare bicycles to motorcycles, I have a different
> question:
>
> I used to ride motorcycles, and tried amateur roadracing for a couple
> of years. Last year, when I bought my first-ever good quality road
> bicycle, I asked the staff at the bike shop if you use countersteering
> to go around fast corners on a bicycle, as you do on a motorcycle
> (pushing the handlebar away from you). They didn't know what I was
> talking about.
>
> So, do you use countersteering on a road bicycle?
>
> Thanks,
> Zelda
>
I do. I don't know if it is who I'm racing/riding with, or my technique,
but I can get around corners faster than 90% of the guys I'm with.

Just as a note: the velodrome at Encino has turns that make you countersteer
to keep on the black line. If you don't, you end up slingshotting up to the
top of the track. It'll catch you out if you're not paying attention.

Mike

Raptor
July 17th 03, 08:03 PM
Zelda wrote:
> Since you compare bicycles to motorcycles, I have a different
> question:
>
> I used to ride motorcycles, and tried amateur roadracing for a couple
> of years. Last year, when I bought my first-ever good quality road
> bicycle, I asked the staff at the bike shop if you use countersteering
> to go around fast corners on a bicycle, as you do on a motorcycle
> (pushing the handlebar away from you). They didn't know what I was
> talking about.
>
> So, do you use countersteering on a road bicycle?
>
> Thanks,
> Zelda

Apparently yes. I say "apparently" because it is in the FAQ, but I've
never conciously done it. It's said to be a subconcious technique, and
I believe I've detected it in my own riding. I get around the corners
okay in competition.

Boy, that sounded like the statement of an expert. Hope it helps.

--
--
Lynn Wallace http://www.xmission.com/~lawall
"I'm not proud. We really haven't done everything we could to protect
our customers. Our products just aren't engineered for security."
--Microsoft VP in charge of Windows OS Development, Brian Valentine.

Race Fan
July 17th 03, 08:49 PM
Countersteering works great for roadbikes, you will just want to
practice a bit. A dirty road surface is not a good spot to practice
since the countersteering puts a hefty lean onto the frame and a dirty
road would result in your wheels sliding out from under you. On rough
roads or gritty roads it is best to put your body heavy into the
corner and keep the bike up-right as possible, this makes the pressure
on the tires more directly down, versus a sharp angle between the tire
and the road.

Good luck!

(Zelda) wrote in message >...
> Since you compare bicycles to motorcycles, I have a different
> question:
>
> I used to ride motorcycles, and tried amateur roadracing for a couple
> of years. Last year, when I bought my first-ever good quality road
> bicycle, I asked the staff at the bike shop if you use countersteering
> to go around fast corners on a bicycle, as you do on a motorcycle
> (pushing the handlebar away from you). They didn't know what I was
> talking about.
>
> So, do you use countersteering on a road bicycle?
>
> Thanks,
> Zelda
>
> "S. Anderson" > wrote in message >...
> > (snip)
> > Incidentally, I hit the racetrack every now and again with my motorcycle and
> > I NEVER touch the rear brake when at the track. However, if you watch the
> > good guys, you can see them sliding the rear tire into corners using the
> > rear brake and engine braking. These guys are able to decode the input from
> > the bike to do those things. I'm simply overwhelmed with all the stuff
> > going on and cannot do the stuff they do. So your idea of front-brake only
> > may be analogous to my motorcycle situation..if you can't reliably operate
> > the rear brake during max braking so that the rear wheel doesn't skid,
> > you're probably better off using the front only.
> >
> > Cheers,
> >
> > Scott..

Dominic Richens
July 17th 03, 10:16 PM
"Zelda" > wrote:
> Since you compare bicycles to motorcycles, I have a different
> question:
>
> I used to ride motorcycles, and tried amateur roadracing for a couple
> of years. Last year, when I bought my first-ever good quality road
> bicycle, I asked the staff at the bike shop if you use
> countersteering
> to go around fast corners on a bicycle, as you do on a motorcycle
> (pushing the handlebar away from you). They didn't know what I was
> talking about.
>
> So, do you use countersteering on a road bicycle?

Yeah, but not consciously. I found myself doing it when caught on the
inside of a sharp 90 degree turn (crit). In fact it must be intuitive
because I was watching my 7 year old daughter countersteer as she was riding
up and down the driveway the other day.

--
Dominic Richens |
"If you're not *outraged*, you're not paying attention!"

S. Anderson
July 17th 03, 10:42 PM
"Zelda" > wrote in message
om...
> Since you compare bicycles to motorcycles, I have a different
> question:
>
> I used to ride motorcycles, and tried amateur roadracing for a couple
> of years. Last year, when I bought my first-ever good quality road
> bicycle, I asked the staff at the bike shop if you use countersteering
> to go around fast corners on a bicycle, as you do on a motorcycle
> (pushing the handlebar away from you). They didn't know what I was
> talking about.
>
> So, do you use countersteering on a road bicycle?
>
> Thanks,
> Zelda
>

I think the whole countsteer thing is a little over-done. EVERYONE
countersteers when riding a bicycle or motorcycle, whether they know what
it's called or what it's supposed to be. I don't think you can initiate a
turn on a bike at any kind of speed without countersteering. Riding schools
emphasize and encapsulate the idea for students so they know the mechanism
for initiating and maintaining a turn, but everyone who rides does it
whether they know it or not. It's a lot easier to tip a bicycle in than a
motorcycle at each machine's normal operating speeds (say, 100kmh for a
motorcycle and 20kmh for a bicycle) so the countersteer is more obvious on a
motorcycle. You really have to push those clip-ons around to get the thing
to turn in. Much less force is required on a bike, so it's probably harder
for a bicyclist to recognize what's going on, but the mechanism is the same.
That's my take on it anyways.

Cheers,

Scott..

asqui
July 18th 03, 12:27 AM
Race Fan wrote:
> Countersteering works great for roadbikes, you will just want to
> practice a bit. A dirty road surface is not a good spot to practice
> since the countersteering puts a hefty lean onto the frame and a dirty
> road would result in your wheels sliding out from under you. On rough
> roads or gritty roads it is best to put your body heavy into the
> corner and keep the bike up-right as possible, this makes the pressure
> on the tires more directly down, versus a sharp angle between the tire
> and the road.
>
> Good luck!

Sheldon Brown would disagree:
http://sheldonbrown.com/brakturn.html#leaning

asqui
July 18th 03, 12:30 AM
S. Anderson wrote:
> "Zelda" > wrote in message
> om...
>> Since you compare bicycles to motorcycles, I have a different
>> question:
>>
>> I used to ride motorcycles, and tried amateur roadracing for a couple
>> of years. Last year, when I bought my first-ever good quality road
>> bicycle, I asked the staff at the bike shop if you use
>> countersteering
>> to go around fast corners on a bicycle, as you do on a motorcycle
>> (pushing the handlebar away from you). They didn't know what I was
>> talking about.
>>
>> So, do you use countersteering on a road bicycle?
>>
>> Thanks,
>> Zelda
>>
>
> I think the whole countsteer thing is a little over-done. EVERYONE
> countersteers when riding a bicycle or motorcycle, whether they know
> what it's called or what it's supposed to be. I don't think you can
> initiate a turn on a bike at any kind of speed without
> countersteering. Riding schools emphasize and encapsulate the idea
> for students so they know the mechanism for initiating and
> maintaining a turn, but everyone who rides does it whether they know
> it or not. It's a lot easier to tip a bicycle in than a motorcycle
> at each machine's normal operating speeds (say, 100kmh for a
> motorcycle and 20kmh for a bicycle) so the countersteer is more
> obvious on a motorcycle. You really have to push those clip-ons
> around to get the thing to turn in. Much less force is required on a
> bike, so it's probably harder for a bicyclist to recognize what's
> going on, but the mechanism is the same. That's my take on it
> anyways.
>
> Cheers,
>
> Scott..

What about leaning your weight? I have seen that other people can rather
competently steer a bike with their hands off the bars. Not through any
hairpins mind you.

David Ryan
July 18th 03, 01:10 AM
asqui wrote:
>
> What about leaning your weight? I have seen that other people can rather
> competently steer a bike with their hands off the bars. Not through any
> hairpins mind you.

Vary the pressure (weight) slightly between the pedals on the downstroke
or stop pedalling with the lower foot in the direction you want to turn
and put a little weight on it. (Either way, you tilt your hips a bit in
that direction.)

Carl Sundquist
July 18th 03, 01:32 AM
"Zelda" > wrote in message
om...
> Since you compare bicycles to motorcycles, I have a different
> question:
>
> I used to ride motorcycles, and tried amateur roadracing for a couple
> of years. Last year, when I bought my first-ever good quality road
> bicycle, I asked the staff at the bike shop if you use countersteering
> to go around fast corners on a bicycle, as you do on a motorcycle
> (pushing the handlebar away from you). They didn't know what I was
> talking about.
>
> So, do you use countersteering on a road bicycle?
>
> Thanks,
> Zelda
>

Yes, you do.

But remember: you can't wheelie a shaft-driven bicycle.

S. Anderson
July 18th 03, 04:31 AM
"Carl Sundquist" > wrote in message
...
>
>
> Yes, you do.
>
> But remember: you can't wheelie a shaft-driven bicycle.
>

Never ridden a shaft-drive bicycle..but you sure can wheelie a shaft-drive
motorcycle!! Course, most bikes with shaft drive aren't happy about being
wheelied..but if ya cane it enough.. ;-)

Cheers,

Scott..

Raptor
July 18th 03, 06:27 AM
An experience from looong ago might relate to this question.

I made the pilgrimmage to the 1983 Coors Classic with my bike stuffed
into the back seat of my '66 Rambler, and tent and sleeping bag in the
trunk. I was a new, enthusiast young pup of a racer from South Dakota,
which of course is a Mecca for racing. In the warmup for the women's
city park criterium, I followed a couple racers around the course on my
bike. We came to a corner. They dove right into it and I was left
thinking, how the hell did they do that, as I lost several meters before
even beginning the turn.

After that, I started practicing "diving" into a turn. I believe I
learned countersteering as a result of that experience.

--
--
Lynn Wallace http://www.xmission.com/~lawall
"I'm not proud. We really haven't done everything we could to protect
our customers. Our products just aren't engineered for security."
--Microsoft VP in charge of Windows OS Development, Brian Valentine.

warren
July 18th 03, 06:47 AM
In article >, Raptor > wrote:

> An experience from looong ago might relate to this question.
>
> I made the pilgrimmage to the 1983 Coors Classic with my bike stuffed
> into the back seat of my '66 Rambler, and tent and sleeping bag in the
> trunk. I was a new, enthusiast young pup of a racer from South Dakota,
> which of course is a Mecca for racing. In the warmup for the women's
> city park criterium, I followed a couple racers around the course on my
> bike. We came to a corner. They dove right into it and I was left
> thinking, how the hell did they do that, as I lost several meters before
> even beginning the turn.
>
> After that, I started practicing "diving" into a turn. I believe I
> learned countersteering as a result of that experience.

Being good in turns has alot more to do with your line, willingness not
to overbrake-especially as you approach the turn, ability to finesse
your way between people going too slow, and having an attitude that
turns are the easiest place to make up ground and every turn is an
opportunity to go as fast as possible without having to pedal.

-WG

Sergio SERVADIO
July 18th 03, 08:12 AM
Silence is often the best headline.
Jobst must still be doing his thing on the Alps.

A bit envious ...

Sergio
Pisa

BikeRacer
July 18th 03, 09:26 AM
warren > wrote:

> > Sorry, perhaps I wasn't clear in my original post. I was referring to
> > emergency braking on a good surface in a straight line. Armstrong was
> > braking in a straight line as he came past the outside of Beloki. This
> > section of the faq states once more that front brake only is the quickest
> > way to decelerate as long as you're not banked in the middle of a turn.
>
> Then it's wrong. Think about my question again...
>
> "Don't you think that having two tires making contact/friction with the
> ground (with the brakes applied) would work better than one?"

Uh, no. Because if the rear wheel still has significant traction,
you aren't applying enough front brake. Because of the weight shift
toward the front, all the traction, and hence braking power, is there.
You can get it to the point where any braking on the rear will make
it slide.

It's true for both motorcycles and bicycles, though the motorcyclists
I know seem to have an easier time grasping this.

Oh, and to the person mentioning certain motorcyclists using the rear
brake to slide the rear end. . . I can't vouch for those particular
motorcyclists, but most don't use the rear brake to do that. Front
braking will unweight the rear so much that throttle can be used to
do that. Rear brake usually used to "trail brake" into a turn, and
take up drivetrain slack just before significant power is applied
to prevent lash.

When it comes to turning, motorcycles diverge from bicycles somewhat
because of the engine. . . there are different techniques available
because of it. Braking is largely the same though.

People always seem to bring up the ability to flip a bike over with the front
brake. Sure, that's possible, but it is exactly that power that makes it
worth using, and using well, to its full potential.

The FAQ and Sheldon are right. Go practice.

asqui
July 18th 03, 11:00 AM
Howard Kveck wrote:
> In article >, "Carl Sundquist"
> > wrote:
>
>
>>
>> But remember: you can't wheelie a shaft-driven bicycle.
>>
>>
>
> Carl, I suspect that about .0005% of the people reading this group
> will have any idea where -that- one came from. Good one.

Well, I managed to find a picture on google to explain what a shaft driven
bicycle is: http://www.rustyspokes.com/images/Image5.jpg
Seems like a radical design concept, but why can't you wheelie it?

Dani

Lindsay
July 18th 03, 12:44 PM
On Thu, 17 Jul 2003 17:46:11 -0400, "S. Anderson"
> wrote:

>"Lindsay" > wrote in message
...
>> Try it and get back to us. BTW - do you think you can produce the
>> same amount of torque to the real wheel of the bike while cornering
>> that you got on the motorcycle?
>>
>> Lindsay
>
>The tricky part is not hitting the pedal on the pavement while leaned over!!
>;-) That's one of the nifty things about motorcycles versus bicycles..big,
>lurid power slides going out of corners...

I grew up in upstate NY and immediately thought of the slides in the
ice racing I used to watch. Try that angle!! ;-)

Lindsay
----------------------------
"One of the annoying things about believing in free
will and individual responsibility is the difficulty
of finding somebody to blame your problems on. And
when you do find somebody, it's remarkable how often
his picture turns up on your driver's license."

P.J. O'Rourke

Lindsay
July 18th 03, 12:46 PM
On Fri, 18 Jul 2003 10:00:12 +0000 (UTC), "asqui"
> wrote:

>Well, I managed to find a picture on google to explain what a shaft driven
>bicycle is: http://www.rustyspokes.com/images/Image5.jpg
>Seems like a radical design concept, but why can't you wheelie it?

Is that titanium?

Lindsay
----------------------------
"One of the annoying things about believing in free
will and individual responsibility is the difficulty
of finding somebody to blame your problems on. And
when you do find somebody, it's remarkable how often
his picture turns up on your driver's license."

P.J. O'Rourke

warren
July 18th 03, 05:11 PM
In article >, BikeRacer
> wrote:

> warren > wrote:
>
> > > Sorry, perhaps I wasn't clear in my original post. I was referring to
> > > emergency braking on a good surface in a straight line. Armstrong was
> > > braking in a straight line as he came past the outside of Beloki. This
> > > section of the faq states once more that front brake only is the quickest
> > > way to decelerate as long as you're not banked in the middle of a turn.
> >
> > Then it's wrong. Think about my question again...
> >
> > "Don't you think that having two tires making contact/friction with the
> > ground (with the brakes applied) would work better than one?"
>
> Uh, no. Because if the rear wheel still has significant traction,
> you aren't applying enough front brake.

I hope I'm never behind you in a race. You are scary.

-WG

BikeRacer
July 19th 03, 12:21 AM
warren > wrote:

> > > "Don't you think that having two tires making contact/friction with the
> > > ground (with the brakes applied) would work better than one?"
> >
> > Uh, no. Because if the rear wheel still has significant traction,
> > you aren't applying enough front brake.
>
> I hope I'm never behind you in a race. You are scary.

No, I am not scary. Let's keep in mind the specific context that was given
by the FAQ and "asqui": emergency braking in straightline, normal traction
conditions. There's nothing scary about that technique in that situation,
the bike is under complete control.

In situations like Beloki's, it isn't clear to me what the proper strategy
would have been, I wasn't there and I don't know what the road looked like
in terms of bumps, camber, or traction.

I disagree with some people when viewing the video. It's clear to me he
locked up the rear wheel to set the slide in motion, which kicked the wheel
out to his left. So he was using too much rear brake. Maybe he hit
an especially slippery spot that helped break it loose. But still - too much
rear brake. Some pepole might say that he was just using the front,
and he used it so much that the rear was "light", and so it slipped to
the left because of the tar, camber, or him starting to lean for the turn.
That's possible. Maybe Beloki will remember and can tell us.

Now, this is easy to say in hindsite, sitting at my computer, but. . .
When the wheel slipped to his left, I think it would have been better for
him to release both brakes to regain traction and then dive into the turn
and hope for the best. He either would have low sided, with less injuries,
or run off the road like Lance. But instead he continued to brake, maybe
with just the front, his rear wheel appeared to come up, and then swung to
the right. When it landed he was pointing in the wrong direction for the
turn, the tire came off, he high sided. Even if the tire didn't blow or come
off the rim he was in no position to make the turn.

So, to summarize, I think poor use of the rear brake set the rear sliding,
and then poor management of the slide led to the actual crash. He was
coming in way too hot for that turn, which probably led him to lean on the rear
brake too much.

warren
July 19th 03, 02:56 AM
In article >, BikeRacer
> wrote:

> warren > wrote:
>
> > > > "Don't you think that having two tires making contact/friction with the
> > > > ground (with the brakes applied) would work better than one?"
> > >


> > > Uh, no. Because if the rear wheel still has significant traction,
> > > you aren't applying enough front brake.

This is a ridiculous statement!

> >
> > I hope I'm never behind you in a race. You are scary.
>
> No, I am not scary. Let's keep in mind the specific context that was given
> by the FAQ and "asqui": emergency braking in straightline, normal traction
> conditions. There's nothing scary about that technique in that situation,
> the bike is under complete control.

You'd have more control and reduce speed quicker with some braking
applied to the rear wheel than none. Period. You also push your weight
back a bit to put more weight on the rear wheel so it grabs/adheres to
the pavement better. This allows for more braking power. Period.

> So, to summarize, I think poor use of the rear brake set the rear sliding,

#1) Tell us then, in a straight line like Beloki was in, how do you get
your rear wheel to go out to the side if the rear wheel is braked too
much and the front is not braked enough? That would be a straight skid.

> He was
> coming in way too hot for that turn, which probably led him to lean on the rear
> brake too much.

It's a very fine line between too much braking on one wheel or the
other and just enough.

#2) Tell us, in this precarious situation, and knowing that if you hit
some slick or loose road surface a wheel with even a tiny amount of
braking could slip, which wheel would you rather apply just a little
too much brake to?

#3) And to clarify, are you saying we should not use any rear brake at
all when we want to reduce speed rapidly in a straight line?

I need the advice from you because 3 weeks ago in a race I had to go
from 28mph to 5mph in about 30 feet before hitting the bars of a guy on
the ground. While I was slowing down this rapidly I managed to push
myself about an inch or two off the back of my saddle (like Lance did
in that picture when he was trying to slow down quickly to avoid
Beloki), steer about a foot to the right to avoid the head of the first
crasher and then hit the handlebars of a second guy but at such a slow
speed I had a very gentle landing and emerged unhurt. I skidded through
my rear tire. I guess I should have read your FAQ.

#4) One more question "BikeRacer". How many road or criterium races
have you done Cat 3 or higher?

-WG

Tom Kunich
July 19th 03, 03:34 AM
Lance isn't nearly as great a rider as you are.

"asqui" > wrote in message
...
> In the footage of Beloki's spectacular crash it can be seen that
Armstrong
> briefly locks up his rear wheel as Beloki crashes. I thought on a
decent
> surface the best way to stop was front brake only? I guess that was
feasible
> with the Weinmann brakes on my Eddy Meckx but these Tektro
cantilevers leave
> some braking performance to be desired :(. Anyway, obviously on a
descent
> like that you'll want to use both to distribute the rim heating
evenly, but
> why did Lance lock up the rear? In the emergency situation shouldn't
he have
> been using the front brake exclusively -- exactly for the reason of
avoiding
> a rear wheel skid?
>
> (I will agree that front brake only is a little "eggs in one basket"
because
> if you wash out the front you're pretty much gone, but I'm arguing
based on
> the "front brake only" rule I've heard time and time again.)
>
> Dani
>
>
>

Tom Kunich
July 19th 03, 03:35 AM
"Carl Sundquist" > wrote in message
...
>
> "S. Anderson" > wrote in message
> >
> > Incidentally, I hit the racetrack every now and again with my
motorcycle
> and
> > I NEVER touch the rear brake when at the track. However, if you
watch the
> > good guys, you can see them sliding the rear tire into corners
using the
> > rear brake and engine braking. These guys are able to decode the
input
> from
> > the bike to do those things. I'm simply overwhelmed with all the
stuff
> > going on and cannot do the stuff they do. So your idea of
front-brake
> only
> > may be analogous to my motorcycle situation..if you can't reliably
operate
> > the rear brake during max braking so that the rear wheel doesn't
skid,
> > you're probably better off using the front only.
> >
>
> Take one XR-100, add one steel shoe, mix in a dirt field and you'll
learn
> wonders.
>
> Carl
> Proud attendee
> Kenny Roberts Training Ranch

BS

Tom
Kenny Roberts was a jr. when I was racing.

Carl Sundquist
July 19th 03, 03:49 AM
"Tom Kunich" > wrote in message
> >
> > Take one XR-100, add one steel shoe, mix in a dirt field and you'll
> learn
> > wonders.
> >
> > Carl
> > Proud attendee
> > Kenny Roberts Training Ranch
>
> BS
>
> Tom
> Kenny Roberts was a jr. when I was racing.
>
>

What the hell are you talking about?

S. Anderson
July 19th 03, 04:27 AM
"asqui" > wrote in message
...
>
> What about leaning your weight? I have seen that other people can rather
> competently steer a bike with their hands off the bars. Not through any
> hairpins mind you.
>

Leaning produces the same effect as countersteering. You shift your weight
and start the bike falling over, which is exactly what countersteering does.
But once the lean is initiated, the wheel turns into the direction of the
turn, maintaining an equilibrium which allows you to maintain the turn.
Conciously countersteering just makes the whole thing happen a lot faster,
which allows you to negotiate those hairpins at speed, something you can't
easily do with no-hands. The mechanism of the countersteer occurs any time
a lean angle is introduced into the equation..whether the source is obvious
or not so obvious, it's still there.

Cheers,

Scott..

warren
July 19th 03, 04:48 AM
In article .net>,
Tom Kunich > wrote:

> Lance isn't nearly as great a rider as you are.

But, but Tom, he read it on the internet and his buddies confirmed it!
It must be true!

-WG



>
> "asqui" > wrote in message
> ...
> > In the footage of Beloki's spectacular crash it can be seen that
> Armstrong
> > briefly locks up his rear wheel as Beloki crashes. I thought on a
> decent
> > surface the best way to stop was front brake only? I guess that was
> feasible
> > with the Weinmann brakes on my Eddy Meckx but these Tektro
> cantilevers leave
> > some braking performance to be desired :(. Anyway, obviously on a
> descent
> > like that you'll want to use both to distribute the rim heating
> evenly, but
> > why did Lance lock up the rear? In the emergency situation shouldn't
> he have
> > been using the front brake exclusively -- exactly for the reason of
> avoiding
> > a rear wheel skid?
> >
> > (I will agree that front brake only is a little "eggs in one basket"
> because
> > if you wash out the front you're pretty much gone, but I'm arguing
> based on
> > the "front brake only" rule I've heard time and time again.)
> >
> > Dani
> >
> >
> >

Ryan Cousineau
July 19th 03, 11:19 AM
In article >,
"Kurgan Gringioni" > wrote:

> "BikeRacer" > wrote in message
> m...
> > warren > wrote:
> >
> > When it comes to turning, motorcycles diverge from bicycles somewhat
> > because of the engine. . .

> IMO, they differ because in cycling the rider is the heaviest component of
> the system while in motorcycling the reverse is true. This makes a
> difference in where the center of gravity is - note that in motorcyling, the
> riders hang off the bike towards the inside of the turn while in cycling the
> riders put the bike down, but not their body.

If cyclists get away with that, it's because they will never run out of
ground clearance before they run off the edge of the tire. Motorcyclists
can, which leads them into all kinds of body contortions to get their
bikes more upright.

Motorbikes can also put on power anytime they want, which notably
changes their handling in corners relative to bicycles.

--
Ryan Cousineau, http://www.sfu.ca/~rcousine
President, Fabrizio Mazzoleni Fan Club

Mark McMaster
July 19th 03, 05:55 PM
warren wrote:
> In article >, BikeRacer
> > wrote:
>
>
>>warren > wrote:
>
>>>I hope I'm never behind you in a race. You are scary.
>>
>>No, I am not scary. Let's keep in mind the specific context that was given
>>by the FAQ and "asqui": emergency braking in straightline, normal traction
>>conditions. There's nothing scary about that technique in that situation,
>>the bike is under complete control.
>
>
> You'd have more control and reduce speed quicker with some braking
> applied to the rear wheel than none.

That defies the laws of physics. In a straight line, the
limit of braking is at the pitch over point, the point when
weight has completely shifted to the front wheel and the
rear is about to lift off the ground. At this point, the
rear brake is next to useless, as the rear tire has almost
no traction.

If you rear tire has significant traction, you are not near
the limit of braking.

On a typical road bike, the limit of braking with the front
brake alone is about 1/2 g. The limit of braking with the
rear brake along is about 1/4 g. Using both brakes, the
limit is between these two. At least when riding in a
straight line, using both brakes can not produce maximum
stopping force.


> You also push your weight
> back a bit to put more weight on the rear wheel so it grabs/adheres to
> the pavement better. This allows for more braking power.

Moving weight rearward increases the maximum braking limit -
but not because it gives more rear wheel traction. The
reason is because it increase the limit of braking before
the pitch over point. None-the-less, it is a relatively
small affect, because a cyclist can move their center of
gravity back by no more than a few inches.

>
>
>>So, to summarize, I think poor use of the rear brake set the rear sliding,
>
>
> #1) Tell us then, in a straight line like Beloki was in, how do you get
> your rear wheel to go out to the side if the rear wheel is braked too
> much and the front is not braked enough? That would be a straight skid.

Because as the brakes are applied, the weight balance is
moved forward (regardless of which brake is used). This
means the front wheel gains traction while the rear wheel
losses traction. With reduced traction available at the
rear, excessive rear braking can result in a skid, whereas
with more front wheel braking, it may not.


> #2) Tell us, in this precarious situation, and knowing that if you hit
> some slick or loose road surface a wheel with even a tiny amount of
> braking could slip, which wheel would you rather apply just a little
> too much brake to?

Obvious the rear. Under low traction situations, the
braking limit of both wheels is limited, but with the
forward weight shift, the front wheel still has more
traction available for braking, so much of the braking can
still be done with the front wheel, and it is still possible
to over brake the rear.

> #3) And to clarify, are you saying we should not use any rear brake at
> all when we want to reduce speed rapidly in a straight line?

There is strong argument that the rear brake is not required
at all when stopping in a straight line on clean dry
pavement. The rear brake is there as a back-up, and for
situations of less than ideal traction.

> I need the advice from you because 3 weeks ago in a race I had to go
> from 28mph to 5mph in about 30 feet before hitting the bars of a guy on
> the ground. While I was slowing down this rapidly I managed to push
> myself about an inch or two off the back of my saddle (like Lance did
> in that picture when he was trying to slow down quickly to avoid
> Beloki), steer about a foot to the right to avoid the head of the first
> crasher and then hit the handlebars of a second guy but at such a slow
> speed I had a very gentle landing and emerged unhurt. I skidded through
> my rear tire. I guess I should have read your FAQ.

If you're rear wheel was skidding, you were over-braking the
rear, and should have let up on the rear brake and increased
the front brake. Then perhaps you wouldn't have crashed at all.

Your braking example is interesting one (28mph to 5mph in 30
feet). Not because it shows your mastery of braking, but
because it shows your poor estimation of your braking
capacity. Going from 28mph to 5mph in 30 feet on a standard
upright bicycle is essentially impossible. It would require
a uniform deceleration rate of 0.85 g, impossible to achieve
on an upright racing bike. Deceleration from 28 mph to 5
mph would take a minimum of 50 feet at the limit of braking
(1/2g). But if you were getting any significant rear wheel
traction, you were below that limit, and your stopping
distance would have been further still. Perhaps you should
re-evaluate your perception of your braking ability.


> #4) One more question "BikeRacer". How many road or criterium races
> have you done Cat 3 or higher?

An interesting question, but completely irrelevant to the
discussion. Good braking technique is required for many
types of riding, not just criteriums of "Cat 3 or higher".
For example, descending on steep, twisty roads - and many
"fatty masters" can descend faster many cat 3 (and higher)
racers, simply because of their extra mass/frontal area ratio.



Mark McMaster

David Ryan
July 19th 03, 06:28 PM
Mark McMaster wrote:
>
> If you rear tire has significant traction, you are not near
> the limit of braking.
>
> On a typical road bike, the limit of braking with the front
> brake alone is about 1/2 g. The limit of braking with the
> rear brake along is about 1/4 g. Using both brakes, the
> limit is between these two. At least when riding in a
> straight line, using both brakes can not produce maximum
> stopping force.

Explain this: If you are anywhere near zero traction on the rear,
what would keep you from pivoting around and essentially crashing
as Beloki did? Seems to me that was Beloki's problem, exacerbated
by the fact that the road surface where his back wheel was was
slicker than the front producing near-zero traction at less than
tipping g's. Seems you must keep enough traction to keep from
going sideways in the rear.

Peter Allen
July 19th 03, 10:56 PM
"asqui" > wrote in message >...
> warren wrote:
> > I think you should worry less about invalid "arguments" and spend the
> > time practicing with both brakes and keeping your weight farther back
> > under heavy braking. Don't you think that having two tires making
> > contact/friction with the ground would work better?
> >
> > -WG
>
> So yeah... now that I found out where I read this invalid argument perhaps
> you would like to consult the rec.bicycles.* faq around here:
> http://draco.acs.uci.edu/rbfaq/FAQ/9.17.html
> Eating one's hat is optional.
>
> Dani

Your suggestion does theoretically maximise braking effect. However it
is only better than using both brakes to the point of both wheels
skidding (by which I mean that the wheels are not skidding, but pull
any harder on the brakes and they will) if the centre of gravity of
you plus bike is rising: this will probably be the case if you need to
stop urgently and yank the brakes. If you're lucky, as you apparently
were, you stop before your centre of gravity rises too far, and you
stop quickly. If you are not lucky, or misjudge it ever so slightly,
or hit a tiny pothole or stone, then your centre of gravity rises up,
does a lovely loop over your front wheel, and your head ends up taking
the same impact Beloki's body did. You are probably dead; if you're
really lucky, you're merely paraplegic because your spine snapped just
low enough down.

The other problem with relying on your front brake for a great
majority of the braking is that it then gets very very hot - and if
you're using tyres inflated to very high pressure, or glue-ons, then
they tend to part company from the wheel under stress, you slide
sideways on the road, and get massive road rash and probably a few
nasty broken bones.

Peter

Peter Allen
July 19th 03, 11:05 PM
warren > wrote in message >...
> In article >, asqui
> > wrote:
>
> > Andrew Lee wrote:
> > > "asqui" > wrote
> > >
> > >> warren wrote:
> > >>> I think you should worry less about invalid "arguments" and spend
> > >>> the time practicing with both brakes and keeping your weight
> > >>> farther back under heavy braking. Don't you think that having two
> > >>> tires making contact/friction with the ground would work better?
> > >>>
> > >>> -WG
> > >>
> > >> So yeah... now that I found out where I read this invalid argument
> > >> perhaps you would like to consult the rec.bicycles.* faq around here:
> > >> http://draco.acs.uci.edu/rbfaq/FAQ/9.17.html
> > >> Eating one's hat is optional.
> > >
> > > Try reading this: http://draco.acs.uci.edu/rbfaq/FAQ/9.15.html
> > >
> > > This has more information about braking in the context of corners...
> >
> > Sorry, perhaps I wasn't clear in my original post. I was referring to
> > emergency braking on a good surface in a straight line. Armstrong was
> > braking in a straight line as he came past the outside of Beloki. This
> > section of the faq states once more that front brake only is the quickest
> > way to decelerate as long as you're not banked in the middle of a turn.
>
> Then it's wrong. Think about my question again...
>
> "Don't you think that having two tires making contact/friction with the
> ground (with the brakes applied) would work better than one?"
>
> Why don't you go out and test your theory and that FAQ statement and
> get back to us? Make sure to bring your hat.

You're wrong here - friction, hence braking effect, due to each tyre
is proportional to force down on each tyre. Therefore if the body plus
bike's centre of gravity is not accelerating either up or down, the
braking effect due to using both brakes as hard as possible without
skidding is exactly the same as using just the front so the back wheel
isn't resting on the ground (or at least is not being supported by the
ground). If the body plus bike's centre of gravity is accelerating up
(the back wheel accelerates up off the ground) then the braking effect
due to yanking the front brake will actually be greater than using
both and staying in contact with the road.

This is however not really the point - the point is that if you yank
the front brake doing 50 mph down a hill, you'll be stopping faster
than everyone else for only a small fraction of a second before you go
over the handlebars and land on your head at nearly 50 mph.

Peter

asqui
July 20th 03, 01:53 AM
warren wrote:
> In article >, Mark McMaster
> > wrote:
>
>> warren wrote:
>>> In article >,
>>> BikeRacer > wrote:
>>>
>>>
>>>> warren > wrote:
>>>
>>>>> I hope I'm never behind you in a race. You are scary.
>>>>
>>>> No, I am not scary. Let's keep in mind the specific context that
>>>> was given by the FAQ and "asqui": emergency braking in
>>>> straightline, normal traction conditions. There's nothing scary
>>>> about that technique in that situation, the bike is under complete
>>>> control.
>>>
>>>
>>> You'd have more control and reduce speed quicker with some braking
>>> applied to the rear wheel than none.
>>
>> That defies the laws of physics.
>
> Read what I said. "You'd have more control..."

No, you said "You'd have more control and reduce speed quicker...". The
paragraph quoted immediately below states that the maximal deceleration is
at the pitch-over point where rear braking provides little to no
deceleration. Since the second part of your AND statement is false,
predicate logic tells us that the entire statement is false -- there is no
need to examine the other part.

>> In a straight line, the
>> limit of braking is at the pitch over point, the point when
>> weight has completely shifted to the front wheel and the
>> rear is about to lift off the ground. At this point, the
>> rear brake is next to useless, as the rear tire has almost
>> no traction.
>>
>> If you rear tire has significant traction, you are not near
>> the limit of braking.
>
> Shift your weight back. AND I can steer without too much worry about
> the front wheel locking up. We're talking about racing here, not your
> ideal application of theories.

I believe we are talking about covering the shortest distance whilst braking
in a straight line on a dry, horizontal, paved surface.

>> On a typical road bike, the limit of braking with the front
>> brake alone is about 1/2 g. The limit of braking with the
>> rear brake along is about 1/4 g. Using both brakes, the
>> limit is between these two.
>
>> At least when riding in a
>> straight line, using both brakes can not produce maximum
>> stopping force.
>
> Ridiculous!

Please could you clarify which part of the well structured logical argument
is ridicusous? Your statement is vague and lacks reasoning.

>>> #1) Tell us then, in a straight line like Beloki was in, how do you
>>> get your rear wheel to go out to the side if the rear wheel is
>>> braked too much and the front is not braked enough? That would be a
>>> straight skid.
>>
>> Because as the brakes are applied, the weight balance is
>> moved forward (regardless of which brake is used). This
>> means the front wheel gains traction while the rear wheel
>> losses traction. With reduced traction available at the
>> rear, excessive rear braking can result in a skid, whereas
>> with more front wheel braking, it may not.
>
> You didn't answer the question. "How do you get the rear wheel to go
> to
> the side...?" And you are forgetting the all important ability to
> steer predictably.

On a steep decent with heavy braking on the front and a locked up rear, the
friction between the rear tyre and the ground is pretty close to zero. This
means that it will have a tendancy to come out to the side to try and
"overtake" the front of the bike, which is decelerating strongly. I could be
wrong... What is your argument for why Beloki's rear slid out?

>>> #3) And to clarify, are you saying we should not use any rear brake
>>> at all when we want to reduce speed rapidly in a straight line?
>>
>> There is strong argument that the rear brake is not required
>> at all when stopping in a straight line on clean dry
>> pavement.
>
> Sure. Tell that to the guys who race for a living. You should do the
> comedy circuit because you've got some hilarious mateerial here!

There is no reason to resort to personal insults. A logical argument has
been presented, with clearly laid out reasoning, so if you don't agree just
find a similarly logical counterargument. Are there any relevant aspects of
real world racing that are not accounted for in the model of the situation?
If things in the real world are as you claim, for the reasons you claim,
then the model must be incorrect. Bear in mind however that we are talking
strictly about stopping in a straight line, in the shortest distance
possible, on a good, dry, and level surface.

>>> I need the advice from you because 3 weeks ago in a race I had to go
>>> from 28mph to 5mph in about 30 feet before hitting the bars of a
>>> guy on the ground. While I was slowing down this rapidly I managed
>>> to push myself about an inch or two off the back of my saddle (like
>>> Lance did
>>> in that picture when he was trying to slow down quickly to avoid
>>> Beloki), steer about a foot to the right to avoid the head of the
>>> first crasher and then hit the handlebars of a second guy but at
>>> such a slow speed I had a very gentle landing and emerged unhurt. I
>>> skidded through my rear tire. I guess I should have read your FAQ.
>>
>> If you're rear wheel was skidding, you were over-braking the
>> rear, and should have let up on the rear brake and increased
>> the front brake. Then perhaps you wouldn't have crashed at all.
>
> Any more front brake and I wouldn't be able to steer and I would
> probably have gone over the bars sooner. I was going to hit one of the
> guys but I slowed as much as possible before doing so. There was no
> harm in skidding the rear wheel except for the tire damage. You really
> don't understand what's most important in that situation.

Now you are bringing in steering, which immediately makes your example
completely irrelevant to the point being argued. We are talking about
straight-line braking only.

>> Your braking example is interesting one (28mph to 5mph in 30
>> feet). Not because it shows your mastery of braking, but
>> because it shows your poor estimation of your braking
>> capacity. Going from 28mph to 5mph in 30 feet on a standard
>> upright bicycle is essentially impossible. It would require
>> a uniform deceleration rate of 0.85 g, impossible to achieve
>> on an upright racing bike. Deceleration from 28 mph to 5
>> mph would take a minimum of 50 feet at the limit of braking
>> (1/2g).
>
> There was a very slight uphill, and perhaps I was still going 6.2 mph
> when I made impact. My computer showed 28-5. And how can you calculate
> my stopping time or distance if you don't know what tire compound I
> use, the inflation of the tires, the size of the contact patch, my
> amount of weight shift, the road surface or grade, etc.? You don't
> even
> know what you don't know.
>
>>> #4) One more question "BikeRacer". How many road or criterium races
>>> have you done Cat 3 or higher?
>>
>> An interesting question, but completely irrelevant to the
>> discussion.
>
> No it's not. It's guys just like you with all their theories who do
> not
> fully understand the real world application of those theories simply
> because you lack enough real world experience to make an accurate
> assessment.

If the application of the theories is not as expected in the real world then
you need to provide reasons for this, not just fall back on your experience.
"I do it like this and I have been doing so for a long time over many races"
is not sufficient to overthrow a physics based argument which suggests the
contrary to what you are claiming.

> Mark, how many criteriums have you done Cat 3 or better?
I have done none. I did however achieve an A grade in a physics A-Level. I
believe the latter point is of relevance here, as this is a physics based
argument. Not having done any racing this perhaps puts me at a disadvantage
in spotting discrepancies between the model and the real world, so hopefully
this is where come in.

> Hey Mark! Line 3 for you. It's Lance and Beloki. They want to hear
> more
> about your braking theories because you seem to know more about it
> than
> they do. Lance also wants to know if you can get the UCI to remove the
> requirement for a rear brake so he ca be more aero!
>
> -WG

warren
July 20th 03, 03:03 AM
In article >, asqui
> wrote:

> warren wrote:
> > In article >, Mark McMaster
> > > wrote:
> >
> >> warren wrote:
> >>> In article >,
> >>> BikeRacer > wrote:
> >>>
> >>>
> >>>> warren > wrote:
> >>>
> >>>>> I hope I'm never behind you in a race. You are scary.
> >>>>
> >>>> No, I am not scary. Let's keep in mind the specific context that
> >>>> was given by the FAQ and "asqui": emergency braking in
> >>>> straightline, normal traction conditions. There's nothing scary
> >>>> about that technique in that situation, the bike is under complete
> >>>> control.
> >>>
> >>>
> >>> You'd have more control and reduce speed quicker with some braking
> >>> applied to the rear wheel than none.
> >>
> >> That defies the laws of physics.
> >
> > Read what I said. "You'd have more control..."
>
> No, you said "You'd have more control and reduce speed quicker...". The
> paragraph quoted immediately below states that the maximal deceleration is
> at the pitch-over point where rear braking provides little to no
> deceleration.

That theoretical point is of only passing interest to a bike racer
because the two objectives, slowing down while staying in control, are
both important and I have no interest in striving to get my back wheel
just barely lifting off the ground while hoping that my front wheel
doesn't suddenly lose traction. Try to focus on the real world
applications.

> > You didn't answer the question. "How do you get the rear wheel to go
> > to
> > the side...?" And you are forgetting the all important ability to
> > steer predictably.
>
> On a steep decent with heavy braking on the front and a locked up rear, the
> friction between the rear tyre and the ground is pretty close to zero.

If there was no friction on the rear tire there would be no loss of
rubber, and there is loss of rubber.


> >> There is strong argument that the rear brake is not required
> >> at all when stopping in a straight line on clean dry
> >> pavement.
> >
> > Sure. Tell that to the guys who race for a living. You should do the
> > comedy circuit because you've got some hilarious material here!
>
> There is no reason to resort to personal insults.

This guy is silly. His ridiculous comments deserve ridicule.

> > Any more front brake and I wouldn't be able to steer and I would
> > probably have gone over the bars sooner. I was going to hit one of the
> > guys but I slowed as much as possible before doing so. There was no
> > harm in skidding the rear wheel except for the tire damage. You really
> > don't understand what's most important in that situation.
>
> Now you are bringing in steering, which immediately makes your example
> completely irrelevant to the point being argued. We are talking about
> straight-line braking only.

We are talking about the real world of bike racing where there is
always a need for some steering while braking.

> >>> #4) One more question "BikeRacer". How many road or criterium races
> >>> have you done Cat 3 or higher?
> >>
> >> An interesting question, but completely irrelevant to the
> >> discussion.
> >
> > No it's not. It's guys just like you with all their theories who do
> > not
> > fully understand the real world application of those theories simply
> > because you lack enough real world experience to make an accurate
> > assessment.
>
> If the application of the theories is not as expected in the real world then
> you need to provide reasons for this, not just fall back on your experience.

No I don't need to know, or argue the understandings of physics. I need
to know what actually works in a bike race, and I don't always care
about or need to know the physics of why things work the way they do.
An analogy to this, if I told you you need to do a certain type of
training exercise to improve your sprint is it necessary for you or I
to know what is happening at the cellular level in order to carry out
the exercise and derive benefit from it?

> "I do it like this and I have been doing so for a long time over many races"
> is not sufficient to overthrow a physics based argument which suggests the
> contrary to what you are claiming.

I do it much the same way as guys who make their living racing on
bikes. Any decent bike racer does too. The pictures and video of Lance
and Beloki are a fairly accurate representation of how and why I do
what I do in races.


> > Mark, how many criteriums have you done Cat 3 or better?
> I have done none. I did however achieve an A grade in a physics A-Level. I
> believe the latter point is of relevance here, as this is a physics based
> argument. Not having done any racing this perhaps puts me at a disadvantage
> in spotting discrepancies between the model and the real world, so hopefully
> this is where come in.

I doubt that you know enough about physics (who does?) to explain all
the intricate factors and their interplay during something as dynamic
as braking on a bicycle on an imperfect surface like a paved road. At
least you (unlike Mark) understand there may be limits to your "book"
knowledge and that real world experience and testing can sometimes be
the more accurate path for determining what works best.

If you're sure about your ideas concerning braking, go test them at
25-40 mph and tell us what happens. You could have a friend flash a
light at you to indicate that you should initiate a sudden stop or they
could throw something in your path that you have to get around. And to
be consistent with your arguments, do the first half of your testing
using only your front brake.

-WG

asqui
July 20th 03, 07:26 AM
warren wrote:
> In article >, asqui
> > wrote:
>
>> warren wrote:
>>> In article >, Mark McMaster
>>> > wrote:
>>>
>>>> warren wrote:
>>>>> In article >,
>>>>> BikeRacer > wrote:
>>>>>
>>>>>
>>>>>> warren > wrote:
>>>>>
>> On a steep decent with heavy braking on the front and a locked up
>> rear, the friction between the rear tyre and the ground is pretty
>> close to zero.
>
> If there was no friction on the rear tire there would be no loss of
> rubber, and there is loss of rubber.

"Close to zero" does not mean "zero". Let me rephrase: the tyre/road
interface has a very low coefficient of friction when said tyre is skidding
all over the place, when compared to a non-skidding tyre. This point is
supported by the fact that this whole discussion is centered around
preventing skids because they lead to loss of control (due to loss of
coefficient of friction -- much like trying to cycle over an ice patch with
regular tyres.)

Notice however that in the part of my response which you have deleted and
failed to account for in any way (I believe the convention is to at least
use a bracketed elipsis to indicate deletions), I did mention strong braking
on the front -- if, at speed, you jam on the rear only, and skid to a stop,
it is still pretty easy to lose the rear end out one side in the long skid;
this is even moreso if your front is jammed on (because now not only are you
skidding -- leading to a reduction in the coefficient of friction -- but you
are also taking weight off the rear tyre by braking with the front) and that
is why at maximal braking you really don't want to skid the rear.

>> There is no reason to resort to personal insults.
>
> This guy is silly. His ridiculous comments deserve ridicule.

And yet you have still failed to demonstrate this rampant ridiculousness in
any coherent fashion.

>> Now you are bringing in steering, which immediately makes your
>> example completely irrelevant to the point being argued. We are
>> talking about straight-line braking only.
>
> We are talking about the real world of bike racing where there is
> always a need for some steering while braking.

"Always"? Armstrong didn't steer while passing by Beloki's crash.


>> If the application of the theories is not as expected in the real
>> world then you need to provide reasons for this, not just fall back
>> on your experience.
>
> No I don't need to know, or argue the understandings of physics. I need
> to know what actually works in a bike race, and I don't always care
> about or need to know the physics of why things work the way they do.

Well, then your input is going to be of little value to this discussion if
you are unable to translate what you experience in the real world of bike
racing to the world of physics. "According to physics, this happens,
therefore A." "In the real world this is not true." "Why?" "It's just not!"
"But why?" "How many criteriums have you done?" ...

> An analogy to this, if I told you you need to do a certain type of
> training exercise to improve your sprint is it necessary for you or I
> to know what is happening at the cellular level in order to carry out
> the exercise and derive benefit from it?

Well, if you were giving advice I would hope you understood its implications
fully before you started dispensing it, and this would hopefully include
some understanding on a cellular level.

Now, if someone gave a biochemical argument against the efficiency of your
given exercise, then it would be inept to respond with anything other than a
biochemical based counterargument.


>> "I do it like this and I have been doing so for a long time over
>> many races" is not sufficient to overthrow a physics based argument
>> which suggests the contrary to what you are claiming.
>
> I do it much the same way as guys who make their living racing on
> bikes. Any decent bike racer does too. The pictures and video of Lance
> and Beloki are a fairly accurate representation of how and why I do
> what I do in races.

And what if Lance told you that he only grabbed the rear because he
panicked?
Or what if he used the rear because the surface was less than dry?
Beloki is in hospital; I think that's reason enough for you to start
questioning his technique instead of saying "He's a professional therefore
what he is doing *must* be optimal."


>>> Mark, how many criteriums have you done Cat 3 or better?
>> I have done none. I did however achieve an A grade in a physics
>> A-Level. I believe the latter point is of relevance here, as this is
>> a physics based argument. Not having done any racing this perhaps
>> puts me at a disadvantage in spotting discrepancies between the
>> model and the real world, so hopefully this is where come in.
>
> I doubt that you know enough about physics (who does?) to explain all
> the intricate factors and their interplay during something as dynamic
> as braking on a bicycle on an imperfect surface like a paved road. At
> least you (unlike Mark) understand there may be limits to your "book"
> knowledge and that real world experience and testing can sometimes be
> the more accurate path for determining what works best.

I have done real world testing in a steep decent right next to my house.
Braking in a straight line I find that using the rear brake (whilst using
the front strongly) serves only to wear out my rear tyre and aid in a loss
of control.

What Mark is saying is "this is how physics suggests things are...", and if
you think that is incorrect you need to make some sort of reasonable
counterargument that explains why it is incorrect. Just saying that you do
it differently says nothing about the original argument.

> If you're sure about your ideas concerning braking, go test them at
> 25-40 mph and tell us what happens. You could have a friend flash a
> light at you to indicate that you should initiate a sudden stop or
> they
> could throw something in your path that you have to get around. And to
> be consistent with your arguments, do the first half of your testing
> using only your front brake.

Considering we are talking strictly about braking in a straight line on a
good, level, dry surface, throwing something in my path would be entirely
innapropriate.
In any case, I don't have any spare tyres to dedicate to rear-wheel skids.

Dani

Mark McMaster
July 20th 03, 10:39 PM
warren wrote:
> In article >, Mark McMaster
> > wrote:
>
>
>>warren wrote:

>>>You'd have more control and reduce speed quicker with some braking
>>>applied to the rear wheel than none.
>>
>>That defies the laws of physics.
>
>
> Read what I said. "You'd have more control..."

Not necessarily. In many situations, using the just the
front brake gives both better control (decreases the chance
of rear wheel skid) _and_ potential for faster deceleration.


>>At least when riding in a
>>straight line, using both brakes can not produce maximum
>>stopping force.
>
>
> Ridiculous!

No, it is a fact. At the limit of braking, so much weight
has been shifted to the front wheel, that there is not
enough traction at the rear tire to provide any significant
stopping. What is ridiculous is your apparent refutation of
the realities of physics.



>>>#1) Tell us then, in a straight line like Beloki was in, how do you get
>>>your rear wheel to go out to the side if the rear wheel is braked too
>>>much and the front is not braked enough? That would be a straight skid.
>>
>>Because as the brakes are applied, the weight balance is
>>moved forward (regardless of which brake is used). This
>>means the front wheel gains traction while the rear wheel
>>losses traction. With reduced traction available at the
>>rear, excessive rear braking can result in a skid, whereas
>>with more front wheel braking, it may not.
>
>
> You didn't answer the question. "How do you get the rear wheel to go to
> the side...?" And you are forgetting the all important ability to steer
> predictably.

Yes, I did answer the question. Beloki wasn't going in a
completely straight line, he was turning slightly. At a
given braking deceleration, weight will be shifted forward
to a certain degree, decreasing rear traction. This rear
traction can be used for some combination of lateral force
(turning) or longitudinal force (braking). If you use up
too much of the remaining traction in braking force, then
the tire can slip out under lateral force.




>>>#3) And to clarify, are you saying we should not use any rear brake at
>>>all when we want to reduce speed rapidly in a straight line?
>>
>>There is strong argument that the rear brake is not required
>>at all when stopping in a straight line on clean dry
>>pavement.
>
>
> Sure. Tell that to the guys who race for a living.

Someone has already be beaten me to it. Keith Code has made
his living teaching bike handling skills to motorcycle and
bicycle racers. He has also written a book about bicycle
racing technique called, "A Gear Higher: The Bicycle
Racer's Handbook of Techniques". A chapter of this book is
devoted to braking. Here are a few excerpts from that
chapter about the use of the rear brake in road racing:

"Weight Factor: The single most important factor to be
aware of in braking is the weight transfer that occurs when
the brakes are applied. Let's say you are a 160-pound rider
and you have a 20 pound bike. During neutral acceleration
with even pedal speed and flat surface conditions, weight
distribution at the wheels is roughly forty-five percent
front and fifty-five percent rear. A routine
non-aggressive, brake application transfers about
seventy-five percent to the front wheel, leaving around
twenty-five percent on the rear. The front end now weighs
three times what the rear does.

"At racing speeds, weight transfer from the increased
stopping force is greater still: ninety percent or more of
the weight can transfer to the front, leaving ten percent or
less remaining on the rear. The rear tire, at the ground,
now weighs eighteen pounds or less! Obviously, the rear
brake can only slow or stop eighteen pounds worth of you and
your bicycle. The lion's share of the braking (162 pounds)
can only be done with the front binder.

"Rear Brake Overuse: Overusing the rear brake is so common
as to be almost a fact of life. On the road, many riders
have essentially given up using it for really hard braking.
It requires maximum attention, especially when it causes
the rear end to hop or slide.

"On the road, both sliding and hopping render the bike out
of control. You can't feel good about leaning into a turn
if you are basically out of control with one of the two
points of contact with earth gone. Even on dirt, a locked
rear can be and often is overused as a tool for slowing and
positioning the bike for a turn. Basically, you are stuck
on a sliding mass of meat and metal that only wants to go
straight - probably straight into what the rider didn't want
to hit! The front is where the weight and the stopping are
- not the rear."

So the expert, Keith Code, is saying that the front brake is
the primary brake all the time, and that under the heaviest
braking, the rear probably shouldn't be used at all. If you
truly believe otherwise, perhaps you should open your own
school of performance riding and write your own book.


> You should do the
> comedy circuit because you've got some hilarious mateerial here!

Not nearly as comedic as your continual scoffing despite not
having evidence to support your position, in addition to
continuing insistence that you can brake beyond the physical
limits of a bicycle.



>>If you're rear wheel was skidding, you were over-braking the
>>rear, and should have let up on the rear brake and increased
>>the front brake. Then perhaps you wouldn't have crashed at all.
>
>
> Any more front brake and I wouldn't be able to steer and I would
> probably have gone over the bars sooner. I was going to hit one of the
> guys but I slowed as much as possible before doing so. There was no
> harm in skidding the rear wheel except for the tire damage. You really
> don't understand what's most important in that situation.


Why couldn't you steer with more front brake? The harm in
skidding the rear wheel is that you decrease steering
control if the rear wheel is skidding instead of rolling,
while at the same time adding no significant braking with
that wheel. After all, wasn't it a skidding rear wheel that
brought Beloki down? Perhaps you wouldn't have crashed at
all if you had relied more on your front brake.


>
>>Your braking example is interesting one (28mph to 5mph in 30
>>feet). Not because it shows your mastery of braking, but
>>because it shows your poor estimation of your braking
>>capacity. Going from 28mph to 5mph in 30 feet on a standard
>>upright bicycle is essentially impossible. It would require
>>a uniform deceleration rate of 0.85 g, impossible to achieve
>>on an upright racing bike. Deceleration from 28 mph to 5
>>mph would take a minimum of 50 feet at the limit of braking
>>(1/2g).
>
>
> There was a very slight uphill, and perhaps I was still going 6.2 mph
> when I made impact.

A deceleration from 28mph to 6.2mph in 30 feet still takes a
deceleration of 0.83 g. Even going up a 5% grade only
increases your stopping limit to about 0.57 g - so you still
can not have done what you claim.


> My computer showed 28-5. And how can you calculate
> my stopping time or distance if you don't know what tire compound I
> use, the inflation of the tires, the size of the contact patch, my
> amount of weight shift, the road surface or grade, etc.? You don't even
> know what you don't know.

You gave your initial and final speeds plus distance (28mph
to 5mph in 30 feet) which is all that is required to
determine deceleration rate:

Accel. = [(End Speed)^2 - (Start Speed)^2]/[2*(distance)]

This relationship holds whether it is a bicycle, an
airplane, or the lunar lander. Tire compound, inflation,
etc. are not only not required to determine the deceleration
rate to change velocity within a given distance, they don't
even determine a bicycle's maximum stopping power on clean
dry pavement. Since you are such a great bicycle rider, I'm
sure you know that it is impossible to skid a front tire
while braking in a straight line on clean dry pavement. In
those situations, the front tire has far more traction than
you can use for braking.



>>>#4) One more question "BikeRacer". How many road or criterium races
>>>have you done Cat 3 or higher?
>>
>>An interesting question, but completely irrelevant to the
>>discussion.
>
>
> No it's not. It's guys just like you with all their theories who do not
> fully understand the real world application of those theories simply
> because you lack enough real world experience to make an accurate
> assessment.

Just how do you know how much real world experience I may or
may not have? Do you naturally assume that the more one
understands about science, the less then understand about
practical applications? If so, you are very, very mistaken.
I, and others who understand braking, have plenty of real
world experience, both in races, and actual "real-world"
situations such as mountain descents and emergency traffic
avoidance.



> Mark, how many criteriums have you done Cat 3 or better?

As I mentioned before, this question is irrelevant. But
since you continue to insist in asking - I'm afraid that I
have lost count of the number of criteriums I have raced
with cat. 2 & 3 riders, but I have done my share. Enough to
know that such races are primarily won on the strength of a
competitors legs, hearts and lungs, and to a much lesser
extent on bike handling skills; and enough to know that
achieving cat. 2 or 3 status is far from a guarantee of good
handling skills.

So far your argument has been mostly ad hominen attack, and
little actual evidence to back up your position (other than
your criterium emergency braking example of questionable
accuracy, where you ended up crashing anyway.). It seems
you are trying to win this argument with pure bluster. If
so, you are doing a rather poor job.


Mark McMaster

Kurgan Gringioni
July 20th 03, 11:40 PM
"Ryan Cousineau" > wrote in message
...
> In article >,
> "Kurgan Gringioni" > wrote:
>
> > "BikeRacer" > wrote in message
> > m...
> > > warren > wrote:
> > >
> > > When it comes to turning, motorcycles diverge from bicycles somewhat
> > > because of the engine. . .
>
> > IMO, they differ because in cycling the rider is the heaviest component
of
> > the system while in motorcycling the reverse is true. This makes a
> > difference in where the center of gravity is - note that in motorcyling,
the
> > riders hang off the bike towards the inside of the turn while in cycling
the
> > riders put the bike down, but not their body.
>
> If cyclists get away with that, it's because they will never run out of
> ground clearance before they run off the edge of the tire.



That's not why. We usually don't lean out bikes over that far. It has to do
with the position of the center of gravity relative to the contact patch.

warren
July 21st 03, 04:36 AM
In article >, asqui
> wrote:

> warren wrote:
> > In article >, asqui
> > > wrote:

> > We are talking about the real world of bike racing where there is
> > always a need for some steering while braking.
>
> "Always"? Armstrong didn't steer while passing by Beloki's crash.

This comment indicates how little you know about bike racing skills.

> >> If the application of the theories is not as expected in the real
> >> world then you need to provide reasons for this, not just fall back
> >> on your experience.
> >
> > No I don't need to know, or argue the understandings of physics. I need
> > to know what actually works in a bike race, and I don't always care
> > about or need to know the physics of why things work the way they do.
>
> Well, then your input is going to be of little value to this discussion if
> you are unable to translate what you experience in the real world of bike
> racing to the world of physics. "According to physics, this happens,
> therefore A."

I don't understand the physics terms well enough to say why something
is, but the real world results of countless bike racers shows that what
I'm saying here about braking (and the need for steering) is true.

Your objection is indicative of people who are unable to learn an
athletic skill with great proficiency. Good athletes try to mimic the
movements made by other athletes who are very good at what they do and
have proven with good results that the skill is being done correctly.
They do not try to learn all the physics terms and jargon involved with
the skill before actually trying to learn the skill. You (well probably
not you) but most good racers learn from other bike racers, not from
books about physics.


> "How many criteriums have you done?" ...

Somewhere close to 700, and one more today.
>
> > An analogy to this, if I told you you need to do a certain type of
> > training exercise to improve your sprint is it necessary for you or I
> > to know what is happening at the cellular level in order to carry out
> > the exercise and derive benefit from it?
>
> Well, if you were giving advice I would hope you understood its implications
> fully before you started dispensing it, and this would hopefully include
> some understanding on a cellular level.

The world of physiology is full of at least partly unexplained results.
Once again, if I suggest a particular training exercise it will because
other people have improved their ability by doing it also. For example,
I can suggest many things to improve aspects of a person's sprint, but
even though I probably don't know what is happening at the cellular
level the suggestion can still have substantial merit. There are many
coaches with only minimal understanding of physiology but their own
experience and that of others allows them to make valuable training
suggestions.

> >> "I do it like this and I have been doing so for a long time over
> >> many races" is not sufficient to overthrow a physics based argument
> >> which suggests the contrary to what you are claiming.
> >
> > I do it much the same way as guys who make their living racing on
> > bikes. Any decent bike racer does too. The pictures and video of Lance
> > and Beloki are a fairly accurate representation of how and why I do
> > what I do in races.
>
> And what if Lance told you that he only grabbed the rear because he
> panicked?
> Or what if he used the rear because the surface was less than dry?
> Beloki is in hospital; I think that's reason enough for you to start
> questioning his technique instead of saying "He's a professional therefore
> what he is doing *must* be optimal."

Nope. He did not begin braking soon enough. He may have been distracted
by something like his DS talking in his ear, but what I saw was a
featureless landscape that would make it hard to see an upcoming turn.
If you have ever raced in a parking lot or on an airstrip where the
course is marked off with cones it can be very hard to know exactly
when to begin slowing for a turn unless you have a clear view of the
front. We normally look for things like trees or telephone poles and a
lack of these landmarks is something I've encountered in races so I can
see how Belocki might not have been able to judge where the turn began
until it was too late. His actual braking technique may well have been
the best he could do under the circumstances.

If you really want to know if your "no rear brake needed" idea works
why aren't the pros following your idea? I bow to the experience of a
pro over yours.

> > I doubt that you know enough about physics (who does?) to explain all
> > the intricate factors and their interplay during something as dynamic
> > as braking on a bicycle on an imperfect surface like a paved road. At
> > least you (unlike Mark) understand there may be limits to your "book"
> > knowledge and that real world experience and testing can sometimes be
> > the more accurate path for determining what works best.
>
> I have done real world testing in a steep decent right next to my house.
> Braking in a straight line I find that using the rear brake (whilst using
> the front strongly) serves only to wear out my rear tyre and aid in a loss
> of control.

Why did you use the rear brake? I thought your understanding of physics
told you not to use the rear brake? How about repeating your test on a
flat road where there will be less weight on your front wheel?

> > If you're sure about your ideas concerning braking, go test them at
> > 25-40 mph and tell us what happens. You could have a friend flash a
> > light at you to indicate that you should initiate a sudden stop or
> > they
> > could throw something in your path that you have to get around. And to
> > be consistent with your arguments, do the first half of your testing
> > using only your front brake.
>
> Considering we are talking strictly about braking in a straight line on a
> good, level, dry surface, throwing something in my path would be entirely
> innapropriate.

Nope. It would force you to learn about applying brakes suddenly,
without advance notice, you learn about the reasons why you need to be
able to steer while braking, and you can find out what happens when you
try to do all that with only your front brake. You know, like something
that actually happens in a bike race instead of your laboratory
setting.

> In any case, I don't have any spare tyres to dedicate to rear-wheel skids.

But with all your knowledge about the topic I expect that you would not
be skidding at all.

-WG

warren
July 21st 03, 04:51 AM
In article >, Mark McMaster
> wrote:

> warren wrote:
> > In article >, Mark McMaster
> > > wrote:
> >
> >
> >>warren wrote:
>
> >>>You'd have more control and reduce speed quicker with some braking
> >>>applied to the rear wheel than none.
> >>
> >>That defies the laws of physics.
> >
> >
> > Read what I said. "You'd have more control..."
>
> Not necessarily. In many situations, using the just the
> front brake gives both better control (decreases the chance
> of rear wheel skid) _and_ potential for faster deceleration.

Sure Mark. Why aren't the pros following your advice?


> >>>#3) And to clarify, are you saying we should not use any rear brake at
> >>>all when we want to reduce speed rapidly in a straight line?
> >>
> >>There is strong argument that the rear brake is not required
> >>at all when stopping in a straight line on clean dry
> >>pavement.
> >
> >
> > Sure. Tell that to the guys who race for a living.
>
> Someone has already be beaten me to it.

No, the pros aren't following that guy's advice.

> > You should do the
> > comedy circuit because you've got some hilarious mateerial here!
>
> Not nearly as comedic as your continual scoffing despite not
> having evidence to support your position,

The evidence is on OLN and at bike races. Do a few hundred criteriums
with skilled racers and maybe you'll learn alot more than you know now
about braking and steering.

> > Any more front brake and I wouldn't be able to steer and I would
> > probably have gone over the bars sooner. I was going to hit one of the
> > guys but I slowed as much as possible before doing so. There was no
> > harm in skidding the rear wheel except for the tire damage. You really
> > don't understand what's most important in that situation.
>
>
> Why couldn't you steer with more front brake?

If it skids you can't steer as accurately. It's better to risk skidding
the rear than the front. I would hope a bike racer would already know
this.

> Since you are such a great bicycle rider, I'm
> sure you know that it is impossible to skid a front tire
> while braking in a straight line on clean dry pavement. In
> those situations, the front tire has far more traction than
> you can use for braking.

I guess my eyes have deceived me when I saw it happen all those times.
You really should spend more time racing and learning instead of
relying on your mistaken understanding of the physics.

> >>>#4) One more question "BikeRacer". How many road or criterium races
> >>>have you done Cat 3 or higher?
> >>
> >>An interesting question, but completely irrelevant to the
> >>discussion.
> >
> >
> > No it's not. It's guys just like you with all their theories who do not
> > fully understand the real world application of those theories simply
> > because you lack enough real world experience to make an accurate
> > assessment.
>
> Just how do you know how much real world experience I may or
> may not have?

That's why I asked the question. It would also surprise me if you had
done a few hundred races and still believed what you do, but since you
don't have that experience I'm not as surprised by your beliefs.

> > Mark, how many criteriums have you done Cat 3 or better?
>
> As I mentioned before, this question is irrelevant. But
> since you continue to insist in asking - I'm afraid that I
> have lost count of the number of criteriums I have raced
> with cat. 2 & 3 riders, but I have done my share.

Evasive as usual.

-WG

Mark McMaster
July 22nd 03, 03:28 AM
warren wrote:
> In article >, Mark McMaster
> > wrote:
>
>
>>warren wrote:

>>>Read what I said. "You'd have more control..."
>>
>>Not necessarily. In many situations, using the just the
>>front brake gives both better control (decreases the chance
>>of rear wheel skid) _and_ potential for faster deceleration.
>
>
> Sure Mark. Why aren't the pros following your advice?

You'll have to ask them. However, it been demonstrated many
times that one does not have to have the best bike handling
skills to be a pro. For example, much has been made of Jan
Ullrich's questionable descending skills, and yet he is
regarded as possible the best or 2nd best pro presently
riding. No one questions Chris Boardman's athletic ability,
but he is the only racer I can remember who crashed himself
out of the Tour de France all by himself while wearing the
yellow jersey in a single rider crash on a flat, straight
road in the middle of a stage. And then there is Alex
Zulle, who was constantly falling off his bike -
none-the-less he was one of the top riders in the '90s.
There are plenty of other examples as well.


>>>>>#3) And to clarify, are you saying we should not use any rear brake at
>>>>>all when we want to reduce speed rapidly in a straight line?
>>>>
>>>>There is strong argument that the rear brake is not required
>>>>at all when stopping in a straight line on clean dry
>>>>pavement.
>>>
>>>
>>>Sure. Tell that to the guys who race for a living.
>>
>>Someone has already be beaten me to it.
>
>
> No, the pros aren't following that guy's advice.

The ones who know what they are doing are. For example,
Keith Code's book "A Gear Higher: The Racer's Handbook of
Techniques" includes liner notes from pro downhill racer
Marla Streb, who in the book's introduction credits the
techniques taught by Code for much of her success. Perhaps
you'd like to arrange a bike handling smack-down with Marla,
to see who knows how to use their brakes?


> The evidence is on OLN and at bike races. Do a few hundred criteriums
> with skilled racers and maybe you'll learn alot more than you know now
> about braking and steering.

It is interesting that you pick criteriums to illustrate
braking, when for the most part, criterium racing typically
does not use maximal braking. Firstly, top speeds in
criteriums are frequently slower than for hilly or
mountainous road races, so speed reductions before corners
are often smaller in criteriums than for road race descents.
But more importantly, criteriums tend to be raced in tight
packs, where hard braking adds the danger of being hit by
riders behind. Indeed, it is often said that having to use
the brakes in the last lap of a criterium can cost a racer a
win. If you are frequently using hard braking in
criteriums, I'm glad I don't race with you.

You might be interested in this discussion thread from a
while ago, where it is discussed that good braking technique
is not required for criterium racing:

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&threadm=3DE6
6438.8060606%40sheldonbrown.com&rnum=2&prev=/groups%3Fq%3Dbraking%2Btech
nique%2Bcriteriums%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26selm%3D
3DE66438.8060606%2540sheldonbrown.com%26rnum%3D2

There are plenty of places off the race course where good
braking technique are required - any steep descent with
sharp corners for example, or especially when the unexpected
occurs in traffic (like when a car suddenly appears out of a
side street in front of you). Why do you believe that good
braking is only required on the race course?


>>Why couldn't you steer with more front brake?
>
>
> If it skids you can't steer as accurately. It's better to risk skidding
> the rear than the front. I would hope a bike racer would already know
> this.

You reported that you were going nearly straight. You seem
to be under the impression that skidding a front wheel is
easy to do under these conditions. Go out and try to skid
your front wheel with the front brake. On clean dry
pavement it is nearly impossible, even under the hardest
braking. Until you recognize this fact, you can not
optimize your braking.


>>Since you are such a great bicycle rider, I'm
>>sure you know that it is impossible to skid a front tire
>>while braking in a straight line on clean dry pavement. In
>>those situations, the front tire has far more traction than
>>you can use for braking.
>
>
> I guess my eyes have deceived me when I saw it happen all those times.

Then I guess your eyes have deceived you. Go out and try it
to skid the front wheel sometime just with the front brake.
I doubt you'll be able to do it. Just for the heck of it,
today I tested hard braking with just my front brake several
times. Regardless of how hard or from what speed I applied
the front brake, I could never get the front wheel to give
even a hint of skidding, even a few times when I braked hard
enough to lift the rear wheel of the ground.


> You really should spend more time racing and learning
instead of
> relying on your mistaken understanding of the physics.
>


I've already spent plenty of time racing, and you've shown
that it is your understanding of basic physics that is mistaken.

I've spent enough time racing to know that much of the
crashes and carnage is caused by people who are convinced
that just because they have strong legs, they are
automatically good bike handlers.

It is interesting that in your example to demonstrate your
superior braking skills, you ended up crashing anyway. The
last time I was in a similar situation (in my case, it was
in response to a major crash across the entire road ahead of
me in a full pack of 125 riders while descending the John
Fitch Highway in the Fitchburg Stage Race, where I braked
from about 30mph to 10mph in about 75 feet), instead of
crashing, I bunny hopped the bikes laying in the road ahead
of me. (Well, it wasn't so much a bunny hop, but I was able
to lift my front wheel up and ride over the fallen bikes).
Even under such hard braking, I was able to steer away from
fallen riders laying in the road and instead to a spot where
there were only fallen bikes, and then release the brakes in
time to pull the front wheel up. If you are such an expert
bike handler, why did you still crash?


>>Just how do you know how much real world experience I may or
>>may not have?
>
>
> That's why I asked the question. It would also surprise me if you had
> done a few hundred races and still believed what you do, but since you
> don't have that experience I'm not as surprised by your beliefs.

Well, it turns out you are wrong (again), because I have
easily done over two hundred races (of all types - road
races, criteriums, points races, etc.)



>>>Mark, how many criteriums have you done Cat 3 or better?
>>
>>As I mentioned before, this question is irrelevant. But
>>since you continue to insist in asking - I'm afraid that I
>>have lost count of the number of criteriums I have raced
>>with cat. 2 & 3 riders, but I have done my share.
>
>
> Evasive as usual.


And a pointless veer away from the subject, as usual.


As far as I can tell, your whole argument can be paraphrased
as this:

"Only pro racers can be expert bike handlers, and I'm truly
convinced that I'm a good bike racer, so I must be an expert
bike handler, too. Therefore, despite my lack of
understanding of the underlying physics, people should
believe me when I explain how to brake, even though people
who are recognized experts at teaching bike handling skills
advise different techniques."


Unfortunately, your arguments are long on strutting and
chest-thumping, and short on facts and evidence.


Mark McMaster

warren
July 23rd 03, 04:53 AM
In article >, Mark McMaster
> wrote:

> warren wrote:
> > In article >, Mark McMaster
> > > wrote:
> >
> >
> >>warren wrote:
> >>
> >>>In article >, Mark McMaster
> > wrote:
> >>>
> >>>
> >>>
> >>>>warren wrote:
>
> >>>Sure Mark. Why aren't the pros following your advice?
> >>
> >>You'll have to ask them.
> >
> >
> > I already know why. If you brake hard enough so that your front wheel
> > has 90+% of your bodyweight on it (according to you and your sources)
> > you will have a very difficult time trying to steeer/make subtle
> > corrections. That is nearly always much worse than a slight skid of the
> > rear tire and a good
>
> You seem to misunderstand the weight shift. Weight is
> shifted to the front wheel regardless of which brake you
> use.

I know that, but I'm not interested in shifting as much weight to the
front as you advise because it will have a worse affect on steering
than the way I do it. But then I'm just doing what I see good pros
doing all the time.

> However, in your case, your steering was greatly reduced by
> your insistence on over-braking the rear wheel and skidding.
> If you had slowed at the same deceleration rate but with
> more reliance on the front brake (and less on the rear),
> your rear tire would not have skidded, and your steering
> control would have been better.

Given the situation I was in, and given that a very good pro descender
like Beloki did the same thing, I'm fine with what I did.
>
> A skidding tire has less traction than a non-skidding
> (rolling) tire. At the very least, when you first sensed
> the rear wheel skidding, you should have let off a bit on
> the rear brake lever,

See, you have a poor understanding of what goes on in that brief moment
when I'm trying to avoid running in to the heads of two guys sliding in
front of me who were the two riders right in front me (no time to
prepare), while I slow down as quick as I possibly could under the
circumstances. Neither of us even know exactly how much front brake I
was using but I was still able to steer around something important.

> to stop the skidding and increase
> whatever tire traction was available - you would have
> stopped faster. If you are such a good bike handler, why
> did you allow the rear tire to keep skidding?

Later you say it probably took me 40+ feet to slow down yet my rear
rire lost only about 25% of its tread. I don't think I was skidding
very long.

> So, if you choose to get half of your braking from the rear
> wheel, and I instead allow the front wheel to take 90% of my
> weight, I will stop in a distance at least 20% shorter than
> you will.

But you will have much less reliable/nimble steering around whatever it
is you're trying to avoid.

What happens if I have 90% of my weight on my front wheel and I hit a
slick spot on the pavement or a bump or a bike or body? I think it's
usually better to have less than 90% if there's a chance of hitting
something.

> If won't allow the front wheel to supply the
> majority of your braking, you simply can not maximize braking.

Again, braking is not the only important concern.

> Although she has made her biggest mark in downhill racing,
> Marla Streb races in a very wide variety of events (road &
> off-road, bicycles & motorcycles). If you think she doesn't
> know how to handle a bike on pavement, you are very wrong.
> And again, you seem to be claiming that expert braking is
> only applicable to road racing.

Nope, just that the braking on the road is often very different from
braking off road and the opinion of a MTB racer is not particularly
valuable when the obvious experience and technique of good road pros is
contrary to her method (according to you).

> You seem to think that professional criterium racers know
> the best braking technique.

I didn't say that. I think it can be critically important at times
(contrary to what you said earlier) but I think maximum braking while
trying to avoid something is common for a road racer too.

> "In steep straight descent on a mountain bike, put your
> weight far off the back of the saddle and clamp on the front
> brake. Your rear brake is used, but you will skid if you
> brake hard. The front brake is best for optimal control and
> stopping power on very steep descents like those found on
> the Slickrock Trail in Moab, Utah."

The speed used there is a fraction of what happens in my case and the
example provided by Beloki and the gradient is much different too. The
skill should be performed differently. I use my front brake more when
I'm on my MTB. Your use of MTB braking examples are another indication
that you lack an understanding of the important factors for the road,
and for his racing Phinney always had to use those mushy Dura-Ace
brakes that had poor modulation.

You said:
> >>and I'm truly
> >>convinced that I'm a good bike racer, so I must be an expert
> >>bike handler, too.
> >
> >
> > I'm a better bike-handler than racer.
>
> Says who? No evidence of that has yet been presented.

I know it. I was merely refuting your incorrect assumption about my
opinion that one fact lead to the other.

> >>Therefore, despite my lack of
> >>understanding of the underlying physics, people should
> >>believe me when I explain how to brake,
> >
> >
> > Yes.
>
> So now you are the self-declared expert. My, you truly are
> impressed with yourself.

Not THE expert and lots of guys are better at it than me but the
majority of them also use both brakes for road events for the reasons
I've said, and the fact that I crash less often than the average of my
fellow racers, and am able to pass alot of people who are demonstrating
less accurate braking skills than me does indicate my skill level is
good. And unlike you, I'm not advocating something contrary to the
examples you can see every night on OLN.

Next time I'll just jam on my front brake harder and I'll stop 20%
sooner but I won't be able to avoid hitting the first guy's head
because some dope on the internet told me to put 90% of my weight on my
arms and I couldn't steer as well. "Sorry about the skull fracture but
look, my rear tire is still good!"

-WG

David Ryan
July 23rd 03, 12:30 PM
warren wrote:
>
> In article >, Mark McMaster
> > wrote:
>
> > warren wrote:
> > > In article >, Mark McMaster
> > > > wrote:
> > >
> > >
> > >>warren wrote:
> > >>
> > >>>In article >, Mark McMaster
> > > wrote:
> > >>>
> > >>>
> > >>>
> > >>>>warren wrote:
> >
> > >>>Sure Mark. Why aren't the pros following your advice?
> > >>
> > >>You'll have to ask them.
> > >
> > >
> > > I already know why. If you brake hard enough so that your front wheel
> > > has 90+% of your bodyweight on it (according to you and your sources)
> > > you will have a very difficult time trying to steeer/make subtle
> > > corrections. That is nearly always much worse than a slight skid of the
> > > rear tire and a good
> >
> > You seem to misunderstand the weight shift. Weight is
> > shifted to the front wheel regardless of which brake you
> > use.
>
> I know that, but I'm not interested in shifting as much weight to the
> front as you advise because it will have a worse affect on steering
> than the way I do it. But then I'm just doing what I see good pros
> doing all the time.
>
> > However, in your case, your steering was greatly reduced by
> > your insistence on over-braking the rear wheel and skidding.
> > If you had slowed at the same deceleration rate but with
> > more reliance on the front brake (and less on the rear),
> > your rear tire would not have skidded, and your steering
> > control would have been better.
>
> Given the situation I was in, and given that a very good pro descender
> like Beloki did the same thing, I'm fine with what I did.
> >
> > A skidding tire has less traction than a non-skidding
> > (rolling) tire. At the very least, when you first sensed
> > the rear wheel skidding, you should have let off a bit on
> > the rear brake lever,
>
> See, you have a poor understanding of what goes on in that brief moment
> when I'm trying to avoid running in to the heads of two guys sliding in
> front of me who were the two riders right in front me (no time to
> prepare), while I slow down as quick as I possibly could under the
> circumstances. Neither of us even know exactly how much front brake I
> was using but I was still able to steer around something important.
>
> > to stop the skidding and increase
> > whatever tire traction was available - you would have
> > stopped faster. If you are such a good bike handler, why
> > did you allow the rear tire to keep skidding?
>
> Later you say it probably took me 40+ feet to slow down yet my rear
> rire lost only about 25% of its tread. I don't think I was skidding
> very long.
>
> > So, if you choose to get half of your braking from the rear
> > wheel, and I instead allow the front wheel to take 90% of my
> > weight, I will stop in a distance at least 20% shorter than
> > you will.
>
> But you will have much less reliable/nimble steering around whatever it
> is you're trying to avoid.
>
> What happens if I have 90% of my weight on my front wheel and I hit a
> slick spot on the pavement or a bump or a bike or body? I think it's
> usually better to have less than 90% if there's a chance of hitting
> something.
>
> > If won't allow the front wheel to supply the
> > majority of your braking, you simply can not maximize braking.
>
> Again, braking is not the only important concern.
>
> > Although she has made her biggest mark in downhill racing,
> > Marla Streb races in a very wide variety of events (road &
> > off-road, bicycles & motorcycles). If you think she doesn't
> > know how to handle a bike on pavement, you are very wrong.
> > And again, you seem to be claiming that expert braking is
> > only applicable to road racing.
>
> Nope, just that the braking on the road is often very different from
> braking off road and the opinion of a MTB racer is not particularly
> valuable when the obvious experience and technique of good road pros is
> contrary to her method (according to you).
>
> > You seem to think that professional criterium racers know
> > the best braking technique.
>
> I didn't say that. I think it can be critically important at times
> (contrary to what you said earlier) but I think maximum braking while
> trying to avoid something is common for a road racer too.
>
> > "In steep straight descent on a mountain bike, put your
> > weight far off the back of the saddle and clamp on the front
> > brake. Your rear brake is used, but you will skid if you
> > brake hard. The front brake is best for optimal control and
> > stopping power on very steep descents like those found on
> > the Slickrock Trail in Moab, Utah."
>
> The speed used there is a fraction of what happens in my case and the
> example provided by Beloki and the gradient is much different too. The
> skill should be performed differently. I use my front brake more when
> I'm on my MTB. Your use of MTB braking examples are another indication
> that you lack an understanding of the important factors for the road,
> and for his racing Phinney always had to use those mushy Dura-Ace
> brakes that had poor modulation.
>
> You said:
> > >>and I'm truly
> > >>convinced that I'm a good bike racer, so I must be an expert
> > >>bike handler, too.
> > >
> > >
> > > I'm a better bike-handler than racer.
> >
> > Says who? No evidence of that has yet been presented.
>
> I know it. I was merely refuting your incorrect assumption about my
> opinion that one fact lead to the other.
>
> > >>Therefore, despite my lack of
> > >>understanding of the underlying physics, people should
> > >>believe me when I explain how to brake,
> > >
> > >
> > > Yes.
> >
> > So now you are the self-declared expert. My, you truly are
> > impressed with yourself.
>
> Not THE expert and lots of guys are better at it than me but the
> majority of them also use both brakes for road events for the reasons
> I've said, and the fact that I crash less often than the average of my
> fellow racers, and am able to pass alot of people who are demonstrating
> less accurate braking skills than me does indicate my skill level is
> good. And unlike you, I'm not advocating something contrary to the
> examples you can see every night on OLN.
>
> Next time I'll just jam on my front brake harder and I'll stop 20%
> sooner but I won't be able to avoid hitting the first guy's head
> because some dope on the internet told me to put 90% of my weight on my
> arms and I couldn't steer as well. "Sorry about the skull fracture but
> look, my rear tire is still good!"
>
> -WG

The theoretical computations are accurate.
But I have to wonder if there isn't a lack of reliable scientific data
on its practical application. I think we know you can't go 100% front.
But feelings won't quantify 50%, 75% or 90% to the extent that anyone
can reach a practical analysis where the rubber meets the road.

Mark McMaster
July 24th 03, 03:39 AM
warren wrote:
> In article >, Mark McMaster
> > wrote:
>
>
>>warren wrote:
>>
>>>In article >, Mark McMaster
> wrote:

>>You seem to misunderstand the weight shift. Weight is
>>shifted to the front wheel regardless of which brake you
>>use.
>
>
> I know that, but I'm not interested in shifting as much weight to the
> front as you advise because it will have a worse affect on steering
> than the way I do it.

What affect on steering do you expect from the weight shift?
I think you'll find that weight distribution has less
effect on the ability to steer than you imagine. For
example, the old high wheeler bicycles steered just find
with most of their weight on the front wheel. Watch a BMX
freestyle rider stand on the front axle pegs - they still
steer just fine, too. (Here's an extreme example of
steering with a fully loaded front wheel:
http://www.craigjones.com/record-stoppie.html)


>>So, if you choose to get half of your braking from the rear
>>wheel, and I instead allow the front wheel to take 90% of my
>>weight, I will stop in a distance at least 20% shorter than
>>you will.
>
> But you will have much less reliable/nimble steering around whatever it
> is you're trying to avoid.

Again, I suggest you actually try steering with the majority
of weight on the front wheel before you leap to such
conclusions. You'll find it is more nimble than you
imagine. For example, if you've ever sprinted out of the
saddle, standing directly over the pedals with your chest
over the handlebars, you've probably put about 75% of your
weight on the front wheel. And yet racers do this all the
time in tight pack sprints, which also require nimble
steering. In the more stable position of being on the
saddle (or at least with your legs clamping it) and your
arms in a more braced position, you can easily remain nimble
with 80 or 90% of your weight on the front wheel.

> What happens if I have 90% of my weight on my front wheel and I hit a
> slick spot on the pavement or a bump or a bike or body? I think it's
> usually better to have less than 90% if there's a chance of hitting
> something.

That's odd that you worry about such things, when you race a
lot of criteriums. What if you leaned way over in hard
corner and you bump into someone or hit a slick patch? A
rider with experience and good technique will know how far
they can push their traction, and how to react to the
unexpected. If you so timid about slick pavement or hitting
someone, why do you race criteriums?


>
>>Although she has made her biggest mark in downhill racing,
>>Marla Streb races in a very wide variety of events (road &
>>off-road, bicycles & motorcycles). If you think she doesn't
>>know how to handle a bike on pavement, you are very wrong.
>>And again, you seem to be claiming that expert braking is
>>only applicable to road racing.
>
>
> Nope, just that the braking on the road is often very different from
> braking off road and the opinion of a MTB racer is not particularly
> valuable when the obvious experience and technique of good road pros is
> contrary to her method (according to you).

You seem to boo-hoo a lot of good advice from many sources.
Perhaps you open your eyes a little more, you might
actually learn something. And yes, offroad braking does
have pertinence to road braking - especially in light of the
possibility of "slick spots" you seem to be so worried
about. There may be variations in technique, but the same
basic principles apply - the laws of physics don't suddenly
change when you move from one surface to another.


>>>I'm a better bike-handler than racer.
>>
>>Says who? No evidence of that has yet been presented.
>
>
> I know it.

Well, that certainly proves it - not. Your willful
ignorance of several bike handling related subjects seems to
belie that.




>>So now you are the self-declared expert. My, you truly are
>>impressed with yourself.
>
>
> Not THE expert and lots of guys are better at it than me but the
> majority of them also use both brakes for road events for the reasons
> I've said, and the fact that I crash less often than the average of my
> fellow racers, and am able to pass alot of people who are demonstrating
> less accurate braking skills than me does indicate my skill level is
> good. And unlike you, I'm not advocating something contrary to the
> examples you can see every night on OLN.
>
> Next time I'll just jam on my front brake harder and I'll stop 20%
> sooner but I won't be able to avoid hitting the first guy's head
> because some dope on the internet told me to put 90% of my weight on my
> arms and I couldn't steer as well. "Sorry about the skull fracture but
> look, my rear tire is still good!"

So, if I understand correctly, what the issue boils down to
in your mind is not wanting to shift too much weight onto
the front wheel because it makes steering difficult. I
don't know why you believe that. A bicycle turns by counter
steering and leaning, and front/rear weight distribution
does little to change that. Road bikes have no suspension,
so their steering geometry does not change with weight
shift. It takes little torque to turn the front wheel (even
at speed), and any additional weight shifted onto the front
wheel has no significant affect on that. After all, a
unicycle is highly nimble, even though it puts 100% of its
weight on its front wheel. Racing motorcycles don't seem to
have any problem steering, even when they are braking so
hard they are practically doing a nose-wheelie.

I think you also overestimate the traction demands of
braking. If you were to apply both brakes equally until the
rear tire skidded, you'd be at decelerating at a rate of
about 0.3g - i.e. your tires would have a traction force of
about 30% of the rider/bicycle weight. If you cornered and
leaned over enough to hit a pedal on the ground (about a 35
deg. Lean angle), you'd have a lateral force of about 0.6g,
which requires about twice as much traction force as you
could need with equal front and rear braking. And yet
racers seem to have no problem cornering at the angles and
lateral forces where they can't pedal for fear of hitting a
pedal on the ground. On good pavement, a bike can be
cornered at up to about 1 g (45 degree lean angle). Even
when you consider that the tires are nearly equally weighted
when cornering, that means each tire in a corner can support
a traction force equal to half the weight of the
rider/bicycle. Braking, on the other hand, is limited by
the pitch over point, and the pitch over point is at about
0.5g, which is within the traction that is demanded for
cornering. But there is a key difference, and that is that
under hard braking, the forward weight shift increases the
traction of the front tire, making it even less likely to
skid than in hard cornering. Since we have to brake at less
than the pitch over point, hard braking with primarily the
front brake puts less traction demands on the tires than
hard cornering. And since you are such a good bike handler,
I'm sure you have no problem with cornering traction, so you
shouldn't have problems with braking traction.

Since we're on the issue of traction and skidding: These
are always an issue during all types of riding over any
surface. Surface conditions, speed and terrain contours all
affect traction available for cornering or braking, and a
cyclists must be aware of these at all times, and adjust
their actions accordingly. However, it seems that your
solution to these problems is to simply avoid hard braking
(and its reliance on the front brake) at all times, even
when it is warranted. It seems your fear of the front brake
is preventing you from using it to its full effectiveness
when conditions allow. A better approach would be to learn
appropriate technique for hard braking situations, and
therefore the proper use of the front brake, and practice
it, so that you would have those tools at your disposal when
those situation when it is advantageous. Sure, excessive
front braking may cause problems in some situations; but
there are many, if not more, situations where problems can
be avoided with judicious use of hard front braking. When
that car pulls suddenly pulls out in front of you, pulling
hard on the front brake and loading up the front wheel may
be preferable to the alternative.

On a weekly ride I do, there is a steep (about 10% grade),
somewhat curvy, half mile descent, which ends at an
intersection with a busy road (Waltham St., intersecting
with Lexington St., in Woburn, MA). Just coasting, it is
easy to exceed 40 mph on this hill. I regularly let it fly
to about 40-42 mph, and then brake hard in the last 150 feet
around the last curve before the intersection. Trying to
use equal front and rear braking would result in rear wheel
skidding (and loss of direction control), so I use mostly
front wheel braking. I have yet to skid the front wheel or
go over the handlebars.

By the way, while there are few bicycle riding instruction
courses, there are many motorcycle riding courses. I think
you will agree there are similar concerns for motorcycle
braking (skidding, pitch over). None the less, Most of
these course attempt to teach riders to let go of their fear
of the front brake. See:

http://www.motorcycle.com/mo/mcnews/safe3.html

http://www.geocities.com/armingk/drivingskills_1_1.htm

http://homepage.ntlworld.com/ian.maxwell/What_Training___/Advanced_ridin
g/Braking/braking.html

http://www.nhtsa.dot.gov/people/injury/pedbimot/motorcycle/00-NHT-212-mo
torcycle/motorcycle45-46.html

http://www.webbikeworld.com/Motorcycle-Safety/braking-tips.htm

http://www.motorcyclesafety.org/pages/tips_pages/tips_braking.html


Mark McMaster

asqui
July 24th 03, 08:21 PM
warren wrote:
> Tonight during my warmup I did some testing.
>
> While going down a 4-6% grade at about 12mph I applied about 50% (of
> what I could have applied with full squeezing force) to the front
> brake only and I slowed down rapidly but my rear wheel came off the
> ground
> about 1-2 inches.

And then you pitched over and broke your spine and now you are posting from
hospital using a straw in your mouth? No? What a miracle! Every expert knows
that as soon as the rear wheel leaves the ground the rider will
spontaneously combust, unless of course the rear brake is on full.

> For the next 3 attempts I applied about 50-60% force front brake only
> on a flat section starting at about 21mph and I slowed down rapidly
> but
> I had to exert ALOT of pressure on the bars to keep from getting
> pitched forward. It felt like something close to doing a push-up.

It's okay. Having raced 700+ criteriums at cat 3 and better you have a
strong upper body.

> During the second two of these tests I tried to steer or move the bars
> a bit but it was almost impossible to do anything useful with that
> much pressure on the bars.

Do some more pushups.

> Then I tried 2 tests with rear brake only at about 60-70% and it took
> longer to slow down but it was pretty easy to continue steering.

So basically you just conceded that the original argument, which you
opposed, is correct. Q.E.D. Good game and thanks for playing. See you next
Christmas.

> Then I tried two tests on the flat and a very slight down grade with
> front and rear brakes, each at about 50%. I slowed down pretty fast,
> was able to steer a little, and in one test my rear wheel did some
> very brief (a few inches maybe), intermittent skids.

You were able to steer "a little"? Surely that level of control is not
nearly nimble enough to avoid the cyclist lying in the road ahead, on fire
(because while he was crashing he used the front brake only which made him
combust spontaneously)?

> I tried two tests on a slight upgrade of about 2-5% with a bit more
> braking about 60% pressure on each brake and I slowed down quickly but
> there was more pressure on my arms/bars and steering was a little less
> possible.

You might need to replace your headset if it makes it impossible to steer
while you are braking.

> Now, more than before I'm convinced not to apply more than about 50%
> pressure to my front brake and use 50-60% pressure on the rear brake
> if
> I may need to steer around something while braking hard. If I'm not
> worried about steering I think that something around 60% on the front
> and up to a light/brief skid on the rear is optimal. The likely cost
> of too much front brake is far worse than the likely cost of too much
> rear braking.

Except on 70 degree off-road descents on loose gravel, where traction is
sufficient for braking by sticking a branch in between the spokes of your
front wheel.

> An 8 year old kid knows how to control a rear wheel skid as long as
> they're still able to steer with their front wheel
They haven't raced in any criteriums so they are irrelevant. (I will now
proceed to unceremoniously delete the rest of your paragraph without reading
any useful information it may contain. (Though I'm tempted to point out that
a controlled crash isn't really a relevant form of safe braking.))

> As for your comment about sprinting out of the saddle with 75% weight
> on arms/front wheel... As you may know I do ALOT of sprint training.
Of course! Any professional criterium racer worth his weight in gold does.

> That movement/body position (with slightly bent elbows and arms about
> 80 degrees to the top tube) is not trying to resist being pitched
> forward (you'd better have your arms almost straight for that and at a
> shallower angle than 80 degrees) and it's much easier (compared to
> hard front braking) to keep your arms relatively relaxed during
> sprints.

So your headset is fine but your motor skills are suffering.

....

Mark McMaster
July 25th 03, 12:49 PM
warren wrote:

> Tonight during my warmup I did some testing.
>
> While going down a 4-6% grade at about 12mph I applied about 50% (of
> what I could have applied with full squeezing force) to the front brake
> only and I slowed down rapidly but my rear wheel came off the ground
> about 1-2 inches.
>
> For the next 3 attempts I applied about 50-60% force front brake only
> on a flat section starting at about 21mph and I slowed down rapidly but
> I had to exert ALOT of pressure on the bars to keep from getting
> pitched forward. It felt like something close to doing a push-up.
> During the second two of these tests I tried to steer or move the bars
> a bit but it was almost impossible to do anything useful with that much
> pressure on the bars.
>
> Then I tried 2 tests with rear brake only at about 60-70% and it took
> longer to slow down but it was pretty easy to continue steering.
>
> Then I tried two tests on the flat and a very slight down grade with
> front and rear brakes, each at about 50%. I slowed down pretty fast,
> was able to steer a little, and in one test my rear wheel did some very
> brief (a few inches maybe), intermittent skids.
>
> I tried two tests on a slight upgrade of about 2-5% with a bit more
> braking about 60% pressure on each brake and I slowed down quickly but
> there was more pressure on my arms/bars and steering was a little less
> possible.
>
> Now, more than before I'm convinced not to apply more than about 50%
> pressure to my front brake and use 50-60% pressure on the rear brake if
> I may need to steer around something while braking hard. If I'm not
> worried about steering I think that something around 60% on the front
> and up to a light/brief skid on the rear is optimal. The likely cost of
> too much front brake is far worse than the likely cost of too much rear
> braking.

First a few of comments: As you saw, the front brake is
capable of higher braking rates than the rear. I'm sure you
also recognize that the weight shift (requiring more arm
force to oppose) was due to the deceleration rate, and not
to which brake was actually doing the braking. Although the
rear wheel skidded momentarily a few times using the rear
brakes, even at the much higher deceleration rates with the
front brake, the front wheel didn't skid.

When braking hard and loading up the front wheel, it didn't
actually take more steering torque to turn the front wheel
to steer. Instead it is a matter of muscle control, to
coordinate the small steering forces with the larger forces
needed to oppose the forward shift. Just like a lot of
other riding skills, this is a skill that can be mastered
with practice, and steering will become more nimble and fluid.

Just as a quick illustration, imagine that you had foot pegs
mounted to the rear dropouts (like on a BMX freestyle bike),
and that you stood on these wheel holding onto your
handlebar drops. In this position, it would be very
literally like doing pushups on the handlebar. The overall
front/rear wheel weight distribution would be about the same
as when riding normally, but you'd have far more of your
weight on your arms. As you can imagine, with that much
weight on you arms, it would initially be a bit more
difficult to coordinate your steering motions (even when not
braking). However, with practice, you could learn to be
quite nimble and maneuverable.

Still and all, it is good to develop the reflexes to be able
to maneuver while applying hard braking. It will add an
additional tool that can be utilized when the conditions
require it.

Of course, I'm not recommending that you slam on the brakes
and load up the front wheel every time you brake. Obviously
it would not be recommend when riding in deep sand, or over
washboard ruts. But in those situations where it can be
done and you really need it, it's nice to be able to pull
hard braking techniques out of your bag of bike handling tools.


Mark McMaster

warren
July 25th 03, 04:16 PM
In article >, Mark McMaster
> wrote:

> First a few of comments: As you saw, the front brake is
> capable of higher braking rates than the rear. I'm sure you
> also recognize that the weight shift (requiring more arm
> force to oppose) was due to the deceleration rate, and not
> to which brake was actually doing the braking. Although the
> rear wheel skidded momentarily a few times using the rear
> brakes, even at the much higher deceleration rates with the
> front brake, the front wheel didn't skid.

I think part of Beloki's problem may be that his front wheel hit that
loose or slick patch of pavement or granular stuff on top of the
pavement with a "highly-loaded" front wheel, and the front wheel
slipped a little. He had alot of braking on both wheels but I think his
steering problems are what kept him from being able to skid his rear
wheel to a controlled stop.

> When braking hard and loading up the front wheel, it didn't
> actually take more steering torque to turn the front wheel
> to steer. Instead it is a matter of muscle control, to
> coordinate the small steering forces with the larger forces
> needed to oppose the forward shift. Just like a lot of
> other riding skills, this is a skill that can be mastered
> with practice, and steering will become more nimble and fluid.

I sincerely doubt that. When your arms are trying to oppose the weight
shift the (arm) tension has to be very high to do that. Steering (with
arms. wrist, hands, hips) takes muscles that are as relaxed as possible
and that's along way from the situation where your arms have to provide
resistance to say, 70-90% of your bodyweight, especially if those
correction have to happen very fast and accurately. Remember, in my
case the two guys directly in front of me created an obstacle and that
is not very much time or distance to make a correction.

I don't think the freestyle bike analogy works because the speeds (its
influence on steering corrections) and the dynamics of the weight shift
are so different.

I also don't think the analogy of normal road turns and stopping down a
steep hill are quite the same because not only do you have alot longer
to decide what you want to do, you have alot longer to initiate the
turn, and supple hands and arms are not as important for that type of
turning while braking hard.

-WG

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