Bicycle Stopping Distances

RicodJour wrote:

On Nov 6, 7:58*pm, Anton Berlin wrote:

Maggie, if you can lock up either wheel and heat isn't a problem this
is a stupid argument to make * *Who gives a **** if a wheel locks up
by 300 or 303% *?

We all know best braking is just at the level under lock up.

All of his arguments for the past week have been, at best, stupid.
It's time for a change in meds or some better weed, dude.

Hey Margaret, do me a favor, run this thread by RBT and let's see what
they have to day about you contention.

R

No.

Magilla

Michael Press wrote:

In article ,
MagillaGorilla wrote:

thirty-six wrote:

On 6 Nov, 13:04, MagillaGorilla wrote:

If you really want to increase the effectiveness and stability of your rear brake, you
should mount it to the frame on the FRONT of your seat stays, which is how your front
brake is mounted with respect to the rotation of the rim. Â*What this does is cause the
brake caliper assembly to be pushed into the frame during the entire braking event.
But in standard rear brake mounts, the caliper's entire stability is only by the
mounting bolt and the caliper is bring pulled away from the frame.

Mounting your rear calipers to the front of the rear seat stays will aid in high speed
braking stability by a couple percent. Â*The only reason it's not done like that for
most riders is because of aesthetics. Â*Any mechanic or frame builder will tell you it's
not as good to mount the brake calipers where 99.99% of the people mount it.

Magilla

Huh? If anything you want the front brake behind the mounting so
that with typical rims which have a slight flare to their extremity
the brake pads will move towards the hubs so providing a more
controllable inverse servo. The negative servo effect already exists
with the rear brake and the consequences of a diving rear brake, with
the caliper jamming the tyre, are likely of little concern. Mudguards
will prevent wheel jamming with brake mount failure.

Jackass.

Shut up and listen.

In a typical rear brake mount, the directional rotation of the rear wheel pulls the brake
caliper away from the seat stays/frame via the mounting bolt during braking. If you mount
it on the opposite side, the rotational force of the rim (during braking) will cause the
caliper to be pushed into the frame, giving better stability.

Your front brake is mounted 'correctly' but the rear brake is opposite and only done that
way for aesthetics.

I can see you've never had any technical conversations with mechanics and frame builders. I
have yet to meet one that doesn't know this...And some do it. Here is one framebuilder who
does it (notice the rear brake caliper mounted on the front of the seat stays...this is the
same way your front bake is mounted on your fork and provides better stability)

http://i.pbase.com/o4/68/71868/1/554...707038_IMG.JPG
http://www.campyonly.com/images/modb...8/bike%201.jpg

Mounting the rear brake on the seat stay bridge on the side where
the rotating wheel carries the brake away from the seat stay bridge
means that the brake pads are carried toward the tire where they
can then scrape the tire and cause a tire blow out.

--
Michael Press

No, they will not be carried towards the tire because the caliper cannot be pushed inot the frame
(since it is already mounted flugh with the frame. That's the whole point of doing that. That's
the way your front brake - the most essential brake on a bike - is mounted.

If you mount the rear brake in its "normal" way, the rotational forces of the wheel will pull the
caliper away from the frame and give you less lateral stability and braking force.

Magilla

Howard Kveck wrote:

In article ,
MagillaGorilla wrote:

Howard Kveck wrote:

In article
,
" wrote:

Having your weight
rearward is important but your rear brake still doesn't
do much in a panic stop. Grab it anyway, but don't
expect it to do anything as all your weight shifts to
the front.

Which is one of the reasons Campy has a dual pivot brake (clamps hard
for good braking) for the front and a single pivot one for the rear. The rear
doesn't do that much and you simply don't need that much braking power
on the rim in the back.

If you really want to increase the effectiveness and stability of your rear
brake, youshould mount it to the frame on the FRONT of your seat stays,
which is how your front brake is mounted with respect to the rotation of the
rim. What this does is cause the brake caliper assembly to be pushed into
the frame during the entire braking event. But in standard rear brake
mounts, the caliper's entire stability is only by the mounting bolt and the
caliper is bring pulled away from the frame.

Mounting your rear calipers to the front of the rear seat stays will aid in high
speed braking stability by a couple percent. The only reason it's not done like
that for most riders is because of aesthetics. Any mechanic or frame builder will
tell you it's not as good to mount the brake calipers where 99.99% of the people
mount it.

Mmm, I think if you look at a bike and the direction the wheel is rotating, you'll
see that the rotation is pushing the brake pads toward the stays when the caliper is
mounted on the back, like they almost all are.

Correct. That's what I said. But what you don't seem to understand is this causes the
brake caliper at the MOUNTING BOLT to be pulled away from the frame. Whereas on your
front brake, the roatation force of the wheel is pushing your brake caliper INTO the
frame giving your front brake more stability than your rear brake during heavy braking.




The caliper isn't being supported any
more by the stays either way it's mounted.

Yes it is because during braking, when the front brake shoes are being pulled away from
the fork, the area of the caliper where it attaches to the fork crown is going in the
opposite direction. So when you are braking your front brake caliper is being pushed
into the fork giving it more stability.





Mounted on one side, it's pushing the
stays; mounted on the other, it's pulling them. Either way, it's the same force.

Correct, but when it's pulling away from the stays, the only thing keeping it there is
the mounting bolt. All the stress of the braking is transfered through the mounting
bolt and nut. The bolt itself bends and is not inelastic. And the hold that the bolt
goes through is not perfectly flush with the bolt. But on the front brake, the entire
brake caliper assembly is being forced into the frame which is for the most part
immovable and thus gives better stability.

Talk to any frame builder or any engineer at Shimano or Campy or SRAM and they will all
tell you this. Most good mechanics know this too.




The
mounting bolt will bent toward the wheel when it's mounted on the rear of the stay
and bend away from the tire when it's mounted on the front of the stay.

Correct, except in your front brake, most of the force is transfered into the frame
which is for the most part an immovable object. On the rear brake, the brake caliper is
being pulled into the air away from the frame.

If you are a 250 pound rider (or a tandem bike) and routeinly go down 55 mph descents
and need to stop, you would want your rear brake mounted opposite of where it normally
is.

Magilla




A rear
mounted caliper will move the pads down the rim toward the hub if it bends under hard
braking and up the rim if it's front mounted. So a front mounted caliper will show a
very small increase in clamping because the rim is very slightly wedge shaped (a
Mavic Open Pro measures .780" at the outer edge and .769" at the furthest inside edge
of the brake track). But all that is moot because you can easily lock up a rear wheel
under hard braking. Additional brake clamping on the rear is simply unnecessary.
Which is why I pointed out the reason for Campy's differential brake set up.

--
tanx,
Howard

Caught playing safe
It's a bored game

remove YOUR SHOES to reply, ok?

On Nov 7, 8:44*am, MagillaGorilla wrote:
Howard Kveck wrote:

* *Mmm, I think if you look at a bike and the direction the wheel is rotating, you'll
see that the rotation is pushing the brake pads toward the stays when the caliper is
mounted on the back, like they almost all are.

Correct. *That's what I said. *But what you don't seem to understand is this causes the
brake caliper at the MOUNTING BOLT to be pulled away from the frame. * Whereas on your
front brake, the roatation force of the wheel is pushing your brake caliper INTO the
frame giving your front brake more stability than your rear brake during heavy braking.

The front brake is mounted on the fork, not frame. The rest of your
terminology is also apparently chosen at random.

The caliper isn't being supported any
more by the stays either way it's mounted.

Yes it is because during braking, when the front brake shoes are being pulled away from
the fork, the area of the caliper where it attaches to the fork crown is going in the
opposite direction. *So when you are braking your front brake caliper is being pushed
into the fork giving it more stability.

The brake shoes move forward, and the calipers move back?
Jesus, you are a maroon.
Whip up a force diagram for your own edification.
No need to post it as there are no surprises in the diagram for anyone
else.
But at least you got the fork mounting correct.

Mounted on one side, it's pushing the
stays; mounted on the other, it's pulling them. Either way, it's the same force.

It is so sad that you have to point this out to Mascot.

Correct, but when it's pulling away from the stays, the only thing keeping it there is
the mounting bolt. * All the stress of the braking is transfered through the mounting
bolt and nut. The bolt itself bends and is not inelastic. And the hold that the bolt
goes through is not perfectly flush with the bolt. *But on the front brake, the entire
brake caliper assembly is being forced into the frame which is for the most part
immovable and thus gives better stability.

Damn, back to the frame! You do realize that there is a fork AND a
frame on a bicycle and they are not synonymous, right?

The mounting bolt is elastic, but the frame is immovable...?

Get
your
money
back.

Correct, except in your front brake, most of the force is transfered into the frame
which is for the most part an immovable object. *On the rear brake, the brake caliper is
being pulled into the air away from the frame.

Please describe, for entertainment purposes, the braking forces on a
bicycle that are not "transferred" to the frame.

Your terminology is faulty, your understanding of the physics sketchy,
and knowledge of engineering is non-existent. I've had conversations
with pilots - I don't pretend to understand how to fly a plane.

R

On 7 Nov, 12:58, MagillaGorilla wrote:
thirty-six wrote:

Mechanic/framebuilders use systems that work. *I know two quite well
and have spoken to a handful of others over the years although never
about (bicycle) brake calipers. *I had more important considerations
than this. *Leaving components accessible allows for proper servicing
without frustrating access.

In order to do any meaningful service on a brake caliper, you have to remove it from the frame. *Positing it on either
side fo the seat stays will not matter for any minor maintenance that does not require its removal. * What's there to
service in a brake caliper while mounted to the frame anyway?

First of all, there is no point to ever removing a caliper for service
unless you have it tucked behind the frame structure. Doing so allows
for error in reassembling to the frame. The frequent service involves
an inspection of the brake pad condition and cleaning of debris,
possibly deepening of water channels and checking for smooth action of
the caliper. It will also include adjustment to account for wear in
the pads and possibly aditional cable lubrication. These actions need
to be performed after every 100miles for the checks and take just a
few seconds. With the caliper tucked away, there will be a tendency
to ignore the brake until it's performance is poor or non-existant,
unless it's picked up during pre-race machine examination checks.
Hiding it behind the stays makes everything a little awkward.

It would still (rear caliper in front of stays) produce a servo action
on a v-shape braking surface so resulting in increasing tendency to
skid the rear wheel. Not what I'd want when trail braking as I bank
into a corner. This is why you should use a normal mounted rear brake
for trail braking, the front can be difficult to modulate accurately
enough for trail braking at small forces. It's also a reason (with
normal attatchment) behind less brake squeal from the rear brake/rim
combination.

On 7 Nov, 01:34, William Asher wrote:
Fred Fredburger wrote:
thirty-six wrote:
On 6 Nov, 23:25, RicodJour wrote:
On Nov 6, 6:10 pm, William Asher wrote:

Fred Fredburger wrote:
William Asher wrote:
And you always claimed skills learned in rbt would never be
applicable anywhere else. *
RBT? I thought he was channeling old Star Trek episodes. The
"negative servo" and "inverse servo" are things that should be
said just prior to "reversing the polarity". Does Scotty hang out
in RBT?
Scotty never really went in for techno-babble, that was more of a
TNG thing. *So Geordi LaForge might have said something about the
warp core stability drive having an inverse servo coupling because
the caliper arms were mounting in front of the neutronium struts
holding the axial bearings for the plasma couplers to the
antimatter chamber (in contrast to earlier designs where the
caliper arms were behind the neutronium struts, which led to the
less stable positive servo coupling, even with mudguards), Scotty
would just have said "Aye Captain, but the engines are going to
overheat." *Or so I've heard anyway, I never watched either show. *
Don't admit **** like that in public, you anti-geek geek. *I find
it...fascinating, that you know Geordi's name, and the correct
spelling, but you've never watched the show. *Uh huh - no,
seriously, I'll pull out, you don't have to worry because the check
is in the mail and I've never lied in my life and I've never felt
like this before unless you count last week.

The algorithm is as such - three words strung together. *Plasma
induction coil, or dilithium concentrator coupling. *Three words -
two words just makes you sound stupid.

R

Huh? * If anything you want the aluminium front caliper behind the
ferrous carbon crown so that with typical aluminium section rims
which have a slight flare to their extremity the retarding elastomer
controllers will move towards the central travellator bearing so
providing a more controllable inverse servo coupling. * The negative
servo effect already exists with the rear retarding device and the
consequences of a diving rear brake, with the caliper jamming the
air- filled elastic bearings, are likely of little concern. *Water
repelling covers will prevent wheel jamming with brake mount failure.

I preferred my first go.

Your second attempt has the advantage of including the word "retard".
But they're both very impressive.

You know, retard is to usenet what bacon is to food.

--
Bill Asher

mmmm, bacon.. Fridge, target, go...

On 7 Nov, 16:37, thirty-six wrote:
On 7 Nov, 01:34, William Asher wrote:



Fred Fredburger wrote:
thirty-six wrote:
On 6 Nov, 23:25, RicodJour wrote:
On Nov 6, 6:10 pm, William Asher wrote:

Fred Fredburger wrote:
William Asher wrote:
And you always claimed skills learned in rbt would never be
applicable anywhere else. *
RBT? I thought he was channeling old Star Trek episodes. The
"negative servo" and "inverse servo" are things that should be
said just prior to "reversing the polarity". Does Scotty hang out
in RBT?
Scotty never really went in for techno-babble, that was more of a
TNG thing. *So Geordi LaForge might have said something about the
warp core stability drive having an inverse servo coupling because
the caliper arms were mounting in front of the neutronium struts
holding the axial bearings for the plasma couplers to the
antimatter chamber (in contrast to earlier designs where the
caliper arms were behind the neutronium struts, which led to the
less stable positive servo coupling, even with mudguards), Scotty
would just have said "Aye Captain, but the engines are going to
overheat." *Or so I've heard anyway, I never watched either show.. *
Don't admit **** like that in public, you anti-geek geek. *I find
it...fascinating, that you know Geordi's name, and the correct
spelling, but you've never watched the show. *Uh huh - no,
seriously, I'll pull out, you don't have to worry because the check
is in the mail and I've never lied in my life and I've never felt
like this before unless you count last week.

The algorithm is as such - three words strung together. *Plasma
induction coil, or dilithium concentrator coupling. *Three words -
two words just makes you sound stupid.

R

Huh? * If anything you want the aluminium front caliper behind the
ferrous carbon crown so that with typical aluminium section rims
which have a slight flare to their extremity the retarding elastomer
controllers will move towards the central travellator bearing so
providing a more controllable inverse servo coupling. * The negative
servo effect already exists with the rear retarding device and the
consequences of a diving rear brake, with the caliper jamming the
air- filled elastic bearings, are likely of little concern. *Water
repelling covers will prevent wheel jamming with brake mount failure..

I preferred my first go.

Your second attempt has the advantage of including the word "retard".
But they're both very impressive.

You know, retard is to usenet what bacon is to food.

--
Bill Asher

mmmm, bacon.. *Fridge, *target, *go...

quite nice bacon,egg,cheese,gherkin(pickled),whlolemeal(ish) bread and
butter. And tomato and erm hot (cayene) ketchup

On Nov 6, 7:07*pm, RicodJour wrote:
On Nov 6, 7:58*pm, Anton Berlin wrote:



Maggie, if you can lock up either wheel and heat isn't a problem this
is a stupid argument to make * *Who gives a **** if a wheel locks up
by 300 or 303% *?

We all know best braking is just at the level under lock up.

All of his arguments for the past week have been, at best, stupid.
It's time for a change in meds or some better weed, dude.

Hey Margaret, do me a favor, run this thread by RBT and let's see what
they have to day about you contention.

R

Only Maggie the Girlrilla would spend so much time arguing about
something that he can't benefit financially from.

thirty-six wrote:

On 7 Nov, 12:58, MagillaGorilla wrote:
thirty-six wrote:

Mechanic/framebuilders use systems that work. *I know two quite well
and have spoken to a handful of others over the years although never
about (bicycle) brake calipers. *I had more important considerations
than this. *Leaving components accessible allows for proper servicing
without frustrating access.

In order to do any meaningful service on a brake caliper, you have to remove it from the frame. *Positing it on either
side fo the seat stays will not matter for any minor maintenance that does not require its removal. * What's there to
service in a brake caliper while mounted to the frame anyway?

First of all, there is no point to ever removing a caliper for service
unless you have it tucked behind the frame structure.

Another jackass who thinks "sealed" bearings are actually sealed and can't be contaminated. As far as brake calipers are
concerned, they should be broken down and serviced at least once a year...more if you ride in the rain.




Doing so allows
for error in reassembling to the frame.

Putting them back together is not considered difficult by even a beginner mechanic.


The frequent service involves
an inspection of the brake pad condition and cleaning of debris,
possibly deepening of water channels and checking for smooth action of
the caliper.

Diagnostics are not considered maintenance.




It will also include adjustment to account for wear in
the pads and possibly aditional cable lubrication.

Do me a favor, stop talking like the directions insert that comes with a Shimano 105 brake.


These actions need
to be performed after every 100miles for the checks and take just a
few seconds.

Rain is more of a factor than usage, let alone miles ridden.




With the caliper tucked away, there will be a tendency
to ignore the brake until it's performance is poor or non-existant,
unless it's picked up during pre-race machine examination checks.
Hiding it behind the stays makes everything a little awkward.

No it doesn't because you pull the whole thing off, disassemble it, and then put it back together. It's called
maintenance, not awkwardness.



It would still (rear caliper in front of stays) produce a servo action
on a v-shape braking surface so resulting in increasing tendency to
skid the rear wheel.

So then why do you allow for this on your front brake, according to you, if it's so bad?


Thanks,


Magilla

RicodJour wrote:

On Nov 7, 8:44*am, MagillaGorilla wrote:
Howard Kveck wrote:

* *Mmm, I think if you look at a bike and the direction the wheel is rotating, you'll
see that the rotation is pushing the brake pads toward the stays when the caliper is
mounted on the back, like they almost all are.

Correct. *That's what I said. *But what you don't seem to understand is this causes the
brake caliper at the MOUNTING BOLT to be pulled away from the frame. * Whereas on your
front brake, the roatation force of the wheel is pushing your brake caliper INTO the
frame giving your front brake more stability than your rear brake during heavy braking.

The front brake is mounted on the fork, not frame. The rest of your
terminology is also apparently chosen at random.

Don't be a dick, you know what I mean. I used the word fork every now and then too.






The caliper isn't being supported any
more by the stays either way it's mounted.

Yes it is because during braking, when the front brake shoes are being pulled away from
the fork, the area of the caliper where it attaches to the fork crown is going in the
opposite direction. *So when you are braking your front brake caliper is being pushed
into the fork giving it more stability.

The brake shoes move forward, and the calipers move back?

Yes. You are a total idiot if you don't know that's how the forces transfer on your brakes.




Jesus, you are a maroon.

Okay. And you are a green.



Whip up a force diagram for your own edification.

Hey dumbass....how many ****ing mechanics and frame builders do you think I've spoken to in
my life? I just had a ****ing conversation about this with an engineer who is also a frame
builder. Who the **** do you think you're talking to?



No need to post it as there are no surprises in the diagram for anyone
else.
But at least you got the fork mounting correct.

Mounted on one side, it's pushing the
stays; mounted on the other, it's pulling them. Either way, it's the same force.

It is so sad that you have to point this out to Mascot.

Correct, but when it's pulling away from the stays, the only thing keeping it there is
the mounting bolt. * All the stress of the braking is transfered through the mounting
bolt and nut. The bolt itself bends and is not inelastic. And the hold that the bolt
goes through is not perfectly flush with the bolt. *But on the front brake, the entire
brake caliper assembly is being forced into the frame which is for the most part
immovable and thus gives better stability.

Damn, back to the frame! You do realize that there is a fork AND a
frame on a bicycle and they are not synonymous, right?

Yes. Stop trying to act like I don't know that. Disingenuous arguments will make you lose
credibility.



The mounting bolt is elastic, but the frame is immovable...?

Absolutely. Not only that but the whole that the mounting bolt goes through has some lateral
play in it.



Get
your
money
back.

Correct, except in your front brake, most of the force is transfered into the frame
which is for the most part an immovable object. *On the rear brake, the brake caliper is
being pulled into the air away from the frame.

Please describe, for entertainment purposes, the braking forces on a
bicycle that are not "transferred" to the frame.

They're all transferred to the frame and rim, except on the front brake the caliper is pushed
against the FORK (happy now, mother****er?) which makes braking more stable. On the rear
brake, the forces are transferred through the bolt and nut which does not offer as much
stability.




Your terminology is faulty, your understanding of the physics sketchy,
and knowledge of engineering is non-existent. I've had conversations
with pilots - I don't pretend to understand how to fly a plane.

R

How many engineers at Shimano and SRAM have you spoken to in your life? How about
framebuilders? My guess is ZERO.

Thanks,

Magilla