Bicycle Stopping Distances

On Nov 10, 10:32*am, "
wrote:
On Nov 9, 3:18*pm, MagillaGorilla wrote:



RicodJour wrote:
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.

No no no no. *The front brake transfers most of the force through the mating surface of the
caliper to the FORK. *The front bolt transfers probably 30% of the force. *On the rear brake,
the bolt transfers nearly 100% of the force. *It is true that all the force is ultimately
absorbed by the frame. *But the design of the front bake via its placement on the front of the
FORK makes it a more stable design under high loads and high speeds. *Ask any frame
builder/engineer.

Harry Havnoonian is a frame builder AND mechanical engineer (degree from Drexel). *He mounts
the rear brake in front of the seat stays for this very reason and has been doing it for over
20 years. *Give him a call and he'll tell you why:

http://www.hhracinggroup.com/page6.html

Jesus Christballs.

When a bike moves FORWARD the top of the rim
is moving FORWARD and when you brake, the frictional
force of the rim on the brake tries to pull the brake
FORWARD. *You appear to be pedaling your monkey-bike
BACKWARD. *Are you a fixed gear hipster, or worse yet,
a trackie? *What do trackies know about brakes anyway?

The front brake is pulling on the bolt - the entire force
is on the bolt. *The rear brake when conventionally
mounted is pushed against the seatstay by the braking
force.

I could see making some kind of argument that turning
the brake around would load the structure of the brake
in tension and reduce brake squeal, but with modern
road brake arms that don't flex much (not skinny old
inferior Campy competitors from the 60s) and proper
brake pad toe-in, this is not an issue.

Nim Chimpsky*'s posting on this subject is like a bad issue of an old
Superman comic from the Bizarro world. His description of the forces
is the exact opposite of what is actually happening.

R

* Google it.

On Nov 10, 10:32*am, "
wrote:
On Nov 9, 3:18*pm, MagillaGorilla wrote:



RicodJour wrote:
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.

No no no no. *The front brake transfers most of the force through the mating surface of the
caliper to the FORK. *The front bolt transfers probably 30% of the force. *On the rear brake,
the bolt transfers nearly 100% of the force. *It is true that all the force is ultimately
absorbed by the frame. *But the design of the front bake via its placement on the front of the
FORK makes it a more stable design under high loads and high speeds. *Ask any frame
builder/engineer.

Harry Havnoonian is a frame builder AND mechanical engineer (degree from Drexel). *He mounts
the rear brake in front of the seat stays for this very reason and has been doing it for over
20 years. *Give him a call and he'll tell you why:

http://www.hhracinggroup.com/page6.html

Jesus Christballs.

When a bike moves FORWARD the top of the rim
is moving FORWARD and when you brake, the frictional
force of the rim on the brake tries to pull the brake
FORWARD. *You appear to be pedaling your monkey-bike
BACKWARD.

I think I have found the problem. Nim Chimpsky IS riding backwards.
At least he's wearing his helmet.
http://www.ape-o-naut.org/famous/fam...mages/ham1.jpg

R

" wrote:

On Nov 9, 3:18*pm, MagillaGorilla wrote:
RicodJour wrote:
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.

No no no no. *The front brake transfers most of the force through the mating surface of the
caliper to the FORK. *The front bolt transfers probably 30% of the force. *On the rear brake,
the bolt transfers nearly 100% of the force. *It is true that all the force is ultimately
absorbed by the frame. *But the design of the front bake via its placement on the front of the
FORK makes it a more stable design under high loads and high speeds. *Ask any frame
builder/engineer.

Harry Havnoonian is a frame builder AND mechanical engineer (degree from Drexel). *He mounts
the rear brake in front of the seat stays for this very reason and has been doing it for over
20 years. *Give him a call and he'll tell you why:

http://www.hhracinggroup.com/page6.html


Jesus Christballs.

When a bike moves FORWARD the top of the rim
is moving FORWARD and when you brake, the frictional
force of the rim on the brake tries to pull the brake
FORWARD. You appear to be pedaling your monkey-bike
BACKWARD. Are you a fixed gear hipster, or worse yet,
a trackie? What do trackies know about brakes anyway?

Listen up. The bolt acts as a fulcrum So when one end of the seesaw goes up the other must go
down. It's a physics equation.

When you brake hard on your front brake, the brake caliper will push AGAINST your FORK (opposite
the direction of the rotational forces of the rim). On your rear brake, it is pulling away from
the seat stays (opposite of the rotational force of the wheel).

Try this experiment. Loosen your real caliper mounting bolt to give it a few mm's of play but
while still keeping the caliper attached to the seat stays. Then roll your bike along the ground
and grab the rear brake. You will see the caliper moving AWAY (rearward) from the seat stays,
which is opposite of where you think they will go. Your front brake will also move rearward, not
forward which is why mounting it on the front of the FORK is a more stable, more durable and better
fail-safe design.





The front brake is pulling on the bolt - the entire force
is on the bolt. The rear brake when conventionally
mounted is pushed against the seatstay by the braking
force.

Quiet.



I could see making some kind of argument that turning
the brake around would load the structure of the brake
in tension and reduce brake squeal, but with modern
road brake arms that don't flex much (not skinny old
inferior Campy competitors from the 60s) and proper
brake pad toe-in, this is not an issue.

Ben

You need to ask yourself if you think it is true or false whether I have had this conversation with
many framebuilders and engineers and mechanics. Your logic is like, "Since an airplane is heavier
than air, it can't fly."

While I commend you on your intuitive insight, some issues need more than just guesswork to figure
out. Do the experiment and then come back here and tell us what happened.

Magilla

RicodJour wrote:

On Nov 10, 10:32*am, "
wrote:
On Nov 9, 3:18*pm, MagillaGorilla wrote:



RicodJour wrote:
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.

No no no no. *The front brake transfers most of the force through the mating surface of the
caliper to the FORK. *The front bolt transfers probably 30% of the force. *On the rear brake,
the bolt transfers nearly 100% of the force. *It is true that all the force is ultimately
absorbed by the frame. *But the design of the front bake via its placement on the front of the
FORK makes it a more stable design under high loads and high speeds. *Ask any frame
builder/engineer.

Harry Havnoonian is a frame builder AND mechanical engineer (degree from Drexel). *He mounts
the rear brake in front of the seat stays for this very reason and has been doing it for over
20 years. *Give him a call and he'll tell you why:

http://www.hhracinggroup.com/page6.html

Jesus Christballs.

When a bike moves FORWARD the top of the rim
is moving FORWARD and when you brake, the frictional
force of the rim on the brake tries to pull the brake
FORWARD. *You appear to be pedaling your monkey-bike
BACKWARD. *Are you a fixed gear hipster, or worse yet,
a trackie? *What do trackies know about brakes anyway?

The front brake is pulling on the bolt - the entire force
is on the bolt. *The rear brake when conventionally
mounted is pushed against the seatstay by the braking
force.

I could see making some kind of argument that turning
the brake around would load the structure of the brake
in tension and reduce brake squeal, but with modern
road brake arms that don't flex much (not skinny old
inferior Campy competitors from the 60s) and proper
brake pad toe-in, this is not an issue.

Nim Chimpsky*'s posting on this subject is like a bad issue of an old
Superman comic from the Bizarro world. His description of the forces
is the exact opposite of what is actually happening.

R

* Google it.

Nice try...where's the link, asshole?

Magilla

On Nov 10, 12:17*pm, MagillaGorilla wrote:
RicodJour wrote:

Nim Chimpsky*'s posting on this subject is like a bad issue of an old
Superman comic from the Bizarro world. *His description of the forces
is the exact opposite of what is actually happening.

R

* *Google it.

Nice try...where's the link, asshole?

Google it.

R

On Nov 10, 12:16*pm, MagillaGorilla wrote:
" wrote:

When a bike moves FORWARD the top of the rim
is moving FORWARD and when you brake, the frictional
force of the rim on the brake tries to pull the brake
FORWARD. *You appear to be pedaling your monkey-bike
BACKWARD. *Are you a fixed gear hipster, or worse yet,
a trackie? *What do trackies know about brakes anyway?

Listen up. *The bolt acts as a fulcrum *So when one end of the seesaw goes up the other must go
down. *It's a physics equation.

No, the bolt acts as a beam. The various attachment points may be
fulcrums.

When you brake hard on your front brake, the brake caliper will push AGAINST your FORK (opposite
the direction of the rotational forces of the rim). *On your rear brake, it is pulling away from
the seat stays (opposite of the rotational force of the wheel).

No, the top of the bushing/washer/bolt mounting will push against the
top of the fork, but the bottom will pull away. The reverse happens
on the rear brake mounting. Please note that as the force applied,
for either front or rear brake, is tangential, the force will be the
same (assuming equal braking force being applied to the brake lever
and ignoring cable efficiencies). If the braking force is the same,
the force on the brake bolt will be the same, whether it's in the
front or the rear, regardless of where the brake is mounted, fore or
aft of the frame/fork.

But since the bolt is properly tensioned - hence my reference to the
bolt being a partially post-tensioned cantilevered beam - the bolt
does not actually separate from the frame/fork mounting.

Try this experiment. *Loosen your real caliper mounting bolt to give it a few mm's of play but
while still keeping the caliper attached to the seat stays. *Then roll your bike along the ground
and grab the rear brake. *You will see the caliper moving AWAY (rearward) from the seat stays,
which is opposite of where you think they will go. *Your front brake will also move rearward, not
forward which is why mounting it on the front of the FORK is a more stable, more durable and better
fail-safe design.

You are quite the experimental physicist. Set up an experiment using
an incorrect installation to see what happens when it is correctly set
up. Truly brilliant.

Try this experiment. Switch your brake and derailleur cables, and
shift quickly while you're in a pace line. Report your findings back
here.

Here's another one that should appeal to your penetrating mind.
Loosen all of your spokes completely, then go for a ride. Write up
your findings how this applies to a properly tensioned wheel.

The front brake is pulling on the bolt - the entire force
is on the bolt. *The rear brake when conventionally
mounted is pushed against the seatstay by the braking
force.

Quiet.

Saran wrap.

I could see making some kind of argument that turning
the brake around would load the structure of the brake
in tension and reduce brake squeal, but with modern
road brake arms that don't flex much (not skinny old
inferior Campy competitors from the 60s) and proper
brake pad toe-in, this is not an issue.


You need to ask yourself if you think it is true or false whether I have had this conversation with
many framebuilders and engineers and mechanics. *Your logic is like, "Since an airplane is heavier
than air, it can't fly."

You are, obviously, puffing up your random verbal meanderings from
buttonholing people who are eager to be rid of you. Whatever they
said, whether accurate or not, you clearly didn't understand it.

While I commend you on your intuitive insight, some issues need more than just guesswork to figure
out. *Do the experiment and then come back here and tell us what happened.

The experiment that would fetch a failing grade in a high school
physics class?
I think not.

R

RicodJour wrote:

On Nov 10, 12:17*pm, MagillaGorilla wrote:
RicodJour wrote:

Nim Chimpsky*'s posting on this subject is like a bad issue of an old
Superman comic from the Bizarro world. *His description of the forces
is the exact opposite of what is actually happening.

R

* *Google it.

Nice try...where's the link, asshole?

Google it.

R

Google what? Why make it a ****ing guessing game? I'll tell you why:
because you don't really have a link.

Jackass.

Magilla

RicodJour wrote:

On Nov 10, 10:32*am, "
wrote:
On Nov 9, 3:18*pm, MagillaGorilla wrote:



RicodJour wrote:
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.

No no no no. *The front brake transfers most of the force through the mating surface of the
caliper to the FORK. *The front bolt transfers probably 30% of the force. *On the rear brake,
the bolt transfers nearly 100% of the force. *It is true that all the force is ultimately
absorbed by the frame. *But the design of the front bake via its placement on the front of the
FORK makes it a more stable design under high loads and high speeds. *Ask any frame
builder/engineer.

Harry Havnoonian is a frame builder AND mechanical engineer (degree from Drexel). *He mounts
the rear brake in front of the seat stays for this very reason and has been doing it for over
20 years. *Give him a call and he'll tell you why:

http://www.hhracinggroup.com/page6.html

Jesus Christballs.

When a bike moves FORWARD the top of the rim
is moving FORWARD and when you brake, the frictional
force of the rim on the brake tries to pull the brake
FORWARD. *You appear to be pedaling your monkey-bike
BACKWARD.

I think I have found the problem. Nim Chimpsky IS riding backwards.
At least he's wearing his helmet.
http://www.ape-o-naut.org/famous/fam...mages/ham1.jpg


R = retard


Magilla

MagillaGorilla wrote:
RicodJour wrote:
On Nov 10, 12:17 pm, MagillaGorilla wrote:
RicodJour wrote:
Nim Chimpsky* [...]
* Google it.
Nice try...where's the link, asshole?
Google it.

Google what?

http://en.wikipedia.org/wiki/Nim_Chimpsky

On 10 Nov, 17:16, MagillaGorilla wrote:
" wrote:
On Nov 9, 3:18*pm, MagillaGorilla wrote:
RicodJour wrote:
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.

No no no no. *The front brake transfers most of the force through the mating surface of the
caliper to the FORK. *The front bolt transfers probably 30% of the force. *On the rear brake,
the bolt transfers nearly 100% of the force. *It is true that all the force is ultimately
absorbed by the frame. *But the design of the front bake via its placement on the front of the
FORK makes it a more stable design under high loads and high speeds. *Ask any frame
builder/engineer.

Harry Havnoonian is a frame builder AND mechanical engineer (degree from Drexel). *He mounts
the rear brake in front of the seat stays for this very reason and has been doing it for over
20 years. *Give him a call and he'll tell you why:

http://www.hhracinggroup.com/page6.html

Jesus Christballs.

When a bike moves FORWARD the top of the rim
is moving FORWARD and when you brake, the frictional
force of the rim on the brake tries to pull the brake
FORWARD. *You appear to be pedaling your monkey-bike
BACKWARD. *Are you a fixed gear hipster, or worse yet,
a trackie? *What do trackies know about brakes anyway?

Listen up. *The bolt acts as a fulcrum *So when one end of the seesaw goes up the other must go
down. *It's a physics equation.

When you brake hard on your front brake, the brake caliper will push AGAINST your FORK (opposite
the direction of the rotational forces of the rim). *On your rear brake, it is pulling away from
the seat stays (opposite of the rotational force of the wheel).

Try this experiment. *Loosen your real caliper mounting bolt to give it a few mm's of play but
while still keeping the caliper attached to the seat stays. *Then roll your bike along the ground
and grab the rear brake. *You will see the caliper moving AWAY (rearward) from the seat stays,
which is opposite of where you think they will go. *Your front brake will also move rearward, not
forward which is why mounting it on the front of the FORK is a more stable, more durable and better
fail-safe design.



The front brake is pulling on the bolt - the entire force
is on the bolt. *The rear brake when conventionally
mounted is pushed against the seatstay by the braking
force.

Quiet.



I could see making some kind of argument that turning
the brake around would load the structure of the brake
in tension and reduce brake squeal, but with modern
road brake arms that don't flex much (not skinny old
inferior Campy competitors from the 60s) and proper
brake pad toe-in, this is not an issue.

Ben

You need to ask yourself if you think it is true or false whether I have had this conversation with
many framebuilders and engineers and mechanics. *Your logic is like, "Since an airplane is heavier
than air, it can't fly."

While I commend you on your intuitive insight, some issues need more than just guesswork to figure
out. *Do the experiment and then come back here and tell us what happened.

Magilla

You mean the top edge of the boss of the front brake is the fulcrum.