Bicycle Stopping Distances

On 7 Nov, 19:20, MagillaGorilla wrote:
thirty-six wrote:

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.

I do not use sealed bearings for I have found the magical lubricant
(oil) which saves servicing time on 'open' cup and cone bearings which
means I dont yet need to replace them. Except in my pedals which I
had no choice over for the design required. Failed in 2.1/2 years
through water penetration. I strip them down each year now to check.


Doing so allows
for error in reassembling to the frame.

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

When installing a caliper mounting it is nipped up and the caliper
aligned to the wheel rim on the mounting bolt. Should the phone ring,
the smoke alarm sound or any other one of a multitude of interuptions
happen, it is entirely possible the brake mounting is not tightened up
although it appears to work correctly. During a race it may come lose
and the rider is faced with continuing to use a snatching brake for
which if he does finish in position he may well be disqualified for it
(unlikely but possible) or possibly abandoning.

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.

So you dont do them? What about pad cleaning and adjustment, common
everyday maintenance aided by easy accesibility?

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.

Wouldn't recogfnize it if it slapped me in the face. I've currently
a set of GB side pulls, Weinmann centrepulls and Campag 'monoplanar'
sidepulls. Never needed an instruction leaflet for any brake I've
handled. I was dealing with brakes at around six years of age.

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.

It rains here, much. 100 mile checks seem to be about right. I
prefer not to carry a rain gauge so a 100 mile check or each week
seems to do it for me.

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.

I've explained my reason why I prefer not to remove.



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?

I use the front brake for greater decelleration and the servo action
is beneficial, the back, I use to give a fine control to the
decelleration. Such as when closing hard on another rider or vehicle,
I use the front brake to get my speed close and add in my rear brake
to accurately match speed with position, feeding out the front and
using the rear as necessary. This is much easier than using the front
brake alone. The fine control is still needed on the rear brake to
maximise draughting without getting tangled up. And again, going
hard into a corner may be done on the front brake but a more accurate
control of apex speed may be made with the rear brake so maximising
exit speed from a corner.

I'm not racing, but at least I can feel like I am on the downhill
bits. I can still use my brakes, probably better now.

On Nov 7, 6:44*am, MagillaGorilla wrote:

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.

That doesn't matter as long as it doesn't get pulled off
the frame. It's still transferring the force to the frame.

Brake bolts are sufficiently large diameter (M6) that they
don't bend significantly in normal use. This is good,
because if your brake bolt bends repeatedly when
you apply the brakes normally, it will eventually fail from
metal fatigue, and then you will be up monkey **** creek.

Bent brake bolts happen, but mostly from poor
maintenance, like beater bikes that people ride
around with the bolt loose and sticking out so there's
a bigger lever arm on it. Fortunately people who
ride these bikes (undergrads, DUI guys etc) rarely
go fast enough to do full on panic stops and snap
the bolt.

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.

If you have a problem with braking like this, that isn't going
to help, because if you brake enough to plastically bend the
bolt, let alone pull it away from the frame, you're in trouble.
What you need in those circumstances, and what some
tandem riders use, is a third brake (rear drum).

Ben

thirty-six wrote:

On 7 Nov, 19:20, MagillaGorilla wrote:
thirty-six wrote:

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.

I do not use sealed bearings for I have found the magical lubricant
(oil) which saves servicing time on 'open' cup and cone bearings which
means I dont yet need to replace them.

Use Phil grease, not oil.




Except in my pedals which I
had no choice over for the design required. Failed in 2.1/2 years
through water penetration. I strip them down each year now to check.


Doing so allows
for error in reassembling to the frame.

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

When installing a caliper mounting it is nipped up and the caliper
aligned to the wheel rim on the mounting bolt. Should the phone ring,
the smoke alarm sound or any other one of a multitude of interuptions
happen, it is entirely possible the brake mounting is not tightened up
although it appears to work correctly. During a race it may come lose
and the rider is faced with continuing to use a snatching brake for
which if he does finish in position he may well be disqualified for it
(unlikely but possible) or possibly abandoning.

Don't make mistakes. That what Lance tells his mechanic. You need to treat yourself like Lance's treats his mechnic and
you'll be fine. Don't be a pussy.





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.

So you dont do them? What about pad cleaning and adjustment, common
everyday maintenance aided by easy accesibility?

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.

Wouldn't recogfnize it if it slapped me in the face. I've currently
a set of GB side pulls, Weinmann centrepulls and Campag 'monoplanar'
sidepulls. Never needed an instruction leaflet for any brake I've
handled. I was dealing with brakes at around six years of age.

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.

It rains here, much. 100 mile checks seem to be about right. I
prefer not to carry a rain gauge so a 100 mile check or each week
seems to do it for me.

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.

I've explained my reason why I prefer not to remove.



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?

I use the front brake for greater decelleration and the servo action
is beneficial, the back, I use to give a fine control to the
decelleration. Such as when closing hard on another rider or vehicle,
I use the front brake to get my speed close and add in my rear brake
to accurately match speed with position, feeding out the front and
using the rear as necessary. This is much easier than using the front
brake alone. The fine control is still needed on the rear brake to
maximise draughting without getting tangled up. And again, going
hard into a corner may be done on the front brake but a more accurate
control of apex speed may be made with the rear brake so maximising
exit speed from a corner.

I'm not racing, but at least I can feel like I am on the downhill
bits. I can still use my brakes, probably better now.

On Nov 7, 4:28*pm, "
wrote:
On Nov 7, 6:44*am, MagillaGorilla wrote:

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.

I get a ****ing headache every time I read that. I don't have my
stupid-to-English translator engaged, so tell me this, Batbuoy, are
you arguing that a loose brake bolt is what makes the difference? If
not, and the braking force is the same, as it must be, and all braking
force is transmitted to the frame, as it must be, where does this
extra braking force come from? The bolt, submitted to the same force
in either mounting position, will deflect the same amount as the
difference in geometry is negligible. Much like your argument.

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.

Here's the deal, you work up a free body force diagram and post it,
and I'll get on the horn and talk to Campy. I'll spare your other
little Mr. Softy - you don't even have to plug in numbers, just show
the arrows for the force vectors.

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.

Again with the loose terminology - it's deflecting, and the amount is
truly miniscule.

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.

That doesn't matter as long as it doesn't get pulled off
the frame. *It's still transferring the force to the frame.

Brake bolts are sufficiently large diameter (M6) that they
don't bend significantly in normal use. *This is good,
because if *your brake bolt bends repeatedly when
you apply the brakes normally, it will eventually fail from
metal fatigue, and then you will be up monkey **** creek.

Bent brake bolts happen, but mostly from poor
maintenance, like beater bikes that people ride
around with the bolt loose and sticking out so there's
a bigger lever arm on it. *Fortunately people who
ride these bikes (undergrads, DUI guys etc) rarely
go fast enough to do full on panic stops and snap
the bolt.

(snip MG drivel)

If you have a problem with braking like this, that isn't going
to help, because if you brake enough to plastically bend the
bolt, let alone pull it away from the frame, you're in trouble.
What you need in those circumstances, and what some
tandem riders use, is a third brake (rear drum).

I am at a total loss how these simple facts escape, Mordred. It's
scary and makes me question the education system.

R

" wrote:

On Nov 7, 6:44*am, MagillaGorilla wrote:

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.

That doesn't matter as long as it doesn't get pulled off
the frame. It's still transferring the force to the frame.

No, it does matter. The front brake transfer most of its force to the face of the FORK that
mates with the calipers. The rear brake, the forces are transferred only to the nut threads
and the end of the bolt that holds the brake calipers. The front brake has more lateral
stability because the brake caliper is being pressed super-hard against the frame whereas the
rear brake is being pulled away from the frame and held onto the bike only by the threads on
the nut. The caliper moves less on the front brake under maximum load. The rear brake
design can't away with it because the loads are less than on the front brake by a factor of 3
and the rear brake design - even with the mounting deficiency - is still sufficient to lock
up the wheel. But the front brake...it is essential that it is mounted to the front of the
fork.

If you could somehow mount your front brake to the rear of your fork, and then did maximum
braking on a 55 mph descent, you would eventually see some catastrophic front brake failures
in the peloton over the course f a few years unless gruppos companies beefed up the mounting
bolts.






Brake bolts are sufficiently large diameter (M6) that they
don't bend significantly in normal use. This is good,
because if your brake bolt bends repeatedly when
you apply the brakes normally, it will eventually fail from
metal fatigue, and then you will be up monkey **** creek.

The rear bolt is under 3x less load than the front bolt during a maximum braking effort at
high speed. So this is why the M6 can take the beating and keep on ticking. However, if you
put that same load on the front brake which is subject to 3x the load of the rear brake, you
would eventually see bolt failures. But because most of the load on the front brake is
transferred to the FORK, the bolt is spared the beating it would get had the front brake been
mounted to the rear of the fork as the rear brake is mounted to the seat stays.





Bent brake bolts happen, but mostly from poor
maintenance, like beater bikes that people ride
around with the bolt loose and sticking out so there's
a bigger lever arm on it. Fortunately people who
ride these bikes (undergrads, DUI guys etc) rarely
go fast enough to do full on panic stops and snap
the bolt.

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.

If you have a problem with braking like this, that isn't going
to help, because if you brake enough to plastically bend the
bolt, let alone pull it away from the frame, you're in trouble.
What you need in those circumstances, and what some
tandem riders use, is a third brake (rear drum).

Ben

Always use a superior design and technique. Never accept less than the best.

Magilla

On 8 Nov, 02:25, MagillaGorilla wrote:

Use Phil grease, not oil.
I use a combination of cacium grease which is loaded when the need
arises with cycle oil. Works well. Saves having to dissasemble each
year. I think its ten years(at least) since taking apart my bottom
bracket. Still running sweet.


Don't make mistakes. *That what Lance tells his mechanic. *You need to treat yourself like Lance's treats his mechnic and
you'll be fine. *Don't be a pussy.


The quicker I can perform a service item the more reliable it's going
to be. I'm always looking for shortcuts. Fewer steps reduce the
likelyhood of tripping up.

On Nov 7, 9:42*pm, MagillaGorilla wrote:

But the front brake...it is essential that it is mounted to the front of the
fork.

http://www.bikeradar.com/gallery/art...n-17438?img=16

Maybe you should save the Cervelo engineers a lot of embarrassment and
give them a call to straighten them out.

Just keep digging, Sponge Bob.

R

On 8 Nov, 02:42, MagillaGorilla wrote:
" wrote:
On Nov 7, 6:44*am, MagillaGorilla wrote:

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.

That doesn't matter as long as it doesn't get pulled off
the frame. *It's still transferring the force to the frame.

No, it does matter. *The front brake transfer most of its force to the face of the FORK that
mates with the calipers. *The rear brake, the forces are transferred only to the nut threads
and the end of the bolt that holds the brake calipers. *The front brake has more lateral
stability because the brake caliper is being pressed super-hard against the frame whereas the
rear brake is being pulled away from the frame and held onto the bike only by the threads on
the nut. *The caliper moves less on the front brake under maximum load. *The rear brake
design can't away with it because the loads are less than on the front brake by a factor of 3
and the rear brake design - even with the mounting deficiency - is still sufficient to lock
up the wheel. *But the front brake...it is essential that it is mounted to the front of the
fork.

If you could somehow mount your front brake to the rear of your fork, and then did maximum
braking on a 55 mph descent, you would eventually see some catastrophic front brake failures
in the peloton over the course f a few years unless gruppos companies beefed up the mounting
bolts.



Brake bolts are sufficiently large diameter (M6) that they
don't bend significantly in normal use. *This is good,
because if *your brake bolt bends repeatedly when
you apply the brakes normally, it will eventually fail from
metal fatigue, and then you will be up monkey **** creek.

The rear bolt is under 3x less load than the front bolt during a maximum braking effort at
high speed. *So this is why the M6 can take the beating and keep on ticking. *However, if you
put that same load on the front brake which is subject to 3x the load of the rear brake, you
would eventually see bolt failures. *But because most of the load on the front brake is
transferred to the FORK, the bolt is spared the beating it would get had the front brake been
mounted to the rear of the fork as the rear brake is mounted to the seat stays.





Bent brake bolts happen, but mostly from poor
maintenance, like beater bikes that people ride
around with the bolt loose and sticking out so there's
a bigger lever arm on it. *Fortunately people who
ride these bikes (undergrads, DUI guys etc) rarely
go fast enough to do full on panic stops and snap
the bolt.

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.

If you have a problem with braking like this, that isn't going
to help, because if you brake enough to plastically bend the
bolt, let alone pull it away from the frame, you're in trouble.
What you need in those circumstances, and what some
tandem riders use, is a third brake (rear drum).

Ben

Always use a superior design and technique. *Never accept less than the best.

Magilla

You are wrong. Bending of sidepull mounting bolt is due to torque
upon the caliper arms caused from the drag of the brake pads upon the
rotating rim. If the bolt is made tight enough, this bending strain
does not take place.

On Nov 7, 10:02*pm, thirty-six wrote:

Bending of sidepull mounting bolt is due to torque
upon the caliper arms caused from the drag of the brake pads upon the
rotating rim. *If the bolt is made tight enough, this bending strain
does not take place.

That is not strictly true. If you model the break bolt as a
cantilevered beam, the bolt tightness is analogous to post
tensioning...partial post tensioning. The tightness of the bolt will
affect the deflection, and the bolt between the mounting contact
points will deflect. The deflection with a properly tightened bolt is
totally negligible and could never be a factor by the time you lock up
the wheel.

More to the point Maxipadilla has no idea what he is talking about,
and, if he in fact has had conversations with bike engineers on the
topic, he had no idea what they were talking about. That much is
clear.

R

On Nov 7, 7:01*pm, RicodJour wrote:
On Nov 7, 9:42*pm, MagillaGorilla wrote:



But the front brake...it is essential that it is mounted to the front of the
fork.

http://www.bikeradar.com/gallery/art...-evans-silence...

Maybe you should save the Cervelo engineers a lot of embarrassment and
give them a call to straighten them out.

Just keep digging, Sponge Bob.

R

Dumbass, that's a time trial bike.