Calderazzo feedback brake system

[email hidden] (Max) wrote in message news:<[email hidden]>...

Quoted message said:

Has anyone seen or used something like the Calderazzo feedback brake
system? It has the rear brake on a spring mounting that actuates the
front brake while braking. So you only need one brake lever and it
will stop front braking if the rear wheel leaves the ground.
It looks like this: http://www.thelehmans.net/temp/calderazzo_brakes.gif
from Bicycling Science.

What if the rear wheel starts to skid while you're braking? Since you
can't use the front brake independently of the rear, you'd be left
with no braking at all, wouldn't you? I'd be curious what the experts
say, but given the fact that most hard braking is done with the front
brake, it strikes me as pretty stupid to make the rear brake the
regulator of the whole system.

[email hidden] (Gary Young) wrote in message news:<[email hidden]>...

Quoted message said:

[email hidden] (Max) wrote in message news:<[email hidden]>...

Quoted message said:

Has anyone seen or used something like the Calderazzo feedback brake
system? It has the rear brake on a spring mounting that actuates the
front brake while braking. So you only need one brake lever and it
will stop front braking if the rear wheel leaves the ground.
It looks like this: http://www.thelehmans.net/temp/calderazzo_brakes.gif
from Bicycling Science.

What if the rear wheel starts to skid while you're braking? Since you
can't use the front brake independently of the rear, you'd be left
with no braking at all, wouldn't you? I'd be curious what the experts
say, but given the fact that most hard braking is done with the front
brake, it strikes me as pretty stupid to make the rear brake the
regulator of the whole system.

No, if the rear wheel is is skidding, it would be pushing on the
spring as far as possible, so you would get the most front braking
when the rear wheel skids.

Max

[email hidden] (Max) wrote in message news:<[email hidden]>...

Quoted message said:

[email hidden] (Gary Young) wrote in message news:<[email hidden]>...

Quoted message said:

[email hidden] (Max) wrote in message news:<[email hidden]>...

Quoted message said:

Has anyone seen or used something like the Calderazzo feedback brake
system? It has the rear brake on a spring mounting that actuates the
front brake while braking. So you only need one brake lever and it
will stop front braking if the rear wheel leaves the ground.
It looks like this: http://www.thelehmans.net/temp/calderazzo_brakes.gif
from Bicycling Science.

What if the rear wheel starts to skid while you're braking? Since you
can't use the front brake independently of the rear, you'd be left
with no braking at all, wouldn't you? I'd be curious what the experts
say, but given the fact that most hard braking is done with the front
brake, it strikes me as pretty stupid to make the rear brake the
regulator of the whole system.

No, if the rear wheel is is skidding, it would be pushing on the
spring as far as possible, so you would get the most front braking
when the rear wheel skids.

Yes, but how do you get out of the skid except by letting up on the
rear brake? With this system, letting up on the rear brake means no
front brake either. What happens in a panic stop when you when you
have to use the front brake? Your front braking can be no more
forceful than what would cause the rear wheel to skid. Perhaps that's
all the force you'd ever need, but I'm doubtful.

[email hidden] (Max) wrote in message news:<[email hidden]>...

Quoted message said:

[email hidden] (Gary Young) wrote in message news:<[email hidden]>...

Quoted message said:

[email hidden] (Max) wrote in message news:<[email hidden]>...

Quoted message said:

Has anyone seen or used something like the Calderazzo feedback brake
system? It has the rear brake on a spring mounting that actuates the
front brake while braking. So you only need one brake lever and it
will stop front braking if the rear wheel leaves the ground.
It looks like this: http://www.thelehmans.net/temp/calderazzo_brakes.gif
from Bicycling Science.

What if the rear wheel starts to skid while you're braking? Since you
can't use the front brake independently of the rear, you'd be left
with no braking at all, wouldn't you? I'd be curious what the experts
say, but given the fact that most hard braking is done with the front
brake, it strikes me as pretty stupid to make the rear brake the
regulator of the whole system.

No, if the rear wheel is is skidding, it would be pushing on the
spring as far as possible, so you would get the most front braking
when the rear wheel skids.

Yes, but how do you get out of the skid except by letting up on the
rear brake? With this system, letting up on the rear brake means no
front brake either. What happens in a panic stop when you when you
have to use the front brake? Your front braking can be no more
forceful than what would cause the rear wheel to skid. Perhaps that's
all the force you'd ever need, but I'm doubtful.

[email hidden] (Max) wrote in message news:<[email hidden]>...

Quoted message said:

[email hidden] (Gary Young) wrote in message news:<[email hidden]>...

Quoted message said:

[email hidden] (Max) wrote in message news:<[email hidden]>...

Quoted message said:

Has anyone seen or used something like the Calderazzo feedback brake
system? It has the rear brake on a spring mounting that actuates the
front brake while braking. So you only need one brake lever and it
will stop front braking if the rear wheel leaves the ground.
It looks like this: http://www.thelehmans.net/temp/calderazzo_brakes.gif
from Bicycling Science.

What if the rear wheel starts to skid while you're braking? Since you
can't use the front brake independently of the rear, you'd be left
with no braking at all, wouldn't you? I'd be curious what the experts
say, but given the fact that most hard braking is done with the front
brake, it strikes me as pretty stupid to make the rear brake the
regulator of the whole system.

No, if the rear wheel is is skidding, it would be pushing on the
spring as far as possible, so you would get the most front braking
when the rear wheel skids.

Yes, but how do you get out of the skid except by letting up on the
rear brake? With this system, letting up on the rear brake means no
front brake either. What happens in a panic stop when you when you
have to use the front brake? Your front braking can be no more
forceful than what would cause the rear wheel to skid. Perhaps that's
all the force you'd ever need, but I'm doubtful.

Max Lehman said:

Has anyone seen or used something like the Calderazzo feedback brake
system? It has the rear brake on a spring mounting that actuates
the front brake while braking. So you only need one brake lever and
it will stop front braking if the rear wheel leaves the ground. It
looks like this:

http://www.thelehmans.net/temp/calderazzo_brakes.gif

Quoted message said:

from Bicycling Science.

Could you give a link to an explanation of the value of this brake?
Mention of releasing the front brake if the rear wheel leaves the
ground implies that it is designed to prevent people from "going over
the bars". People who go over the bars do not brake hard enough to
raise the rear wheel anyway so this is an illusion.

http://draco.acs.uci.edu/rbfaq/FAQ/9.36.html

How does Bicycling Science fit into this? This isn't science and as far
as I can see, it doesn't exist in hardware. Can you fill in some blanks?

Jobst Brandt
[email hidden]

[email hidden] wrote in message news:<[email hidden]>...

Quoted message said:

Max Lehman said:

Has anyone seen or used something like the Calderazzo feedback brake
system? It has the rear brake on a spring mounting that actuates
the front brake while braking. So you only need one brake lever and
it will stop front braking if the rear wheel leaves the ground. It
looks like this:

http://www.thelehmans.net/temp/calderazzo_brakes.gif

Quoted message said:

from Bicycling Science.

Could you give a link to an explanation of the value of this brake?
Mention of releasing the front brake if the rear wheel leaves the
ground implies that it is designed to prevent people from "going over
the bars". People who go over the bars do not brake hard enough to
raise the rear wheel anyway so this is an illusion.

http://draco.acs.uci.edu/rbfaq/FAQ/9.36.html

How does Bicycling Science fit into this? This isn't science and as far
as I can see, it doesn't exist in hardware. Can you fill in some blanks?

Jobst Brandt
[email hidden]

I don't have a link to an explanation. The image was scanned from the
book Bicycling Science (third edition) by David Gordon Wilson and is
discussed from page 255. There were 2 main advantages discussed:
(1)if you do start to tip forward, the front brake will release just
long enough to bring the rear wheel back down and (2) you could use
this method to apply "any reasonable degree of force multiplication."
So you could even actuate a coaster brake in the front wheel.

I agree that going over the handlebars would be a rare event for an
experienced rider, but not unheard of, specially on steep hills.

And I agree that it isn't manufactured. I posted this looking for
someone who had tried something similar, or even built their own.

Hope that helps a little,
Max

[email hidden] (Gary Young) wrote in message news:<[email hidden]>...

Quoted message said:

Yes, but how do you get out of the skid except by letting up on the
rear brake? With this system, letting up on the rear brake means no
front brake either. What happens in a panic stop when you when you
have to use the front brake? Your front braking can be no more
forceful than what would cause the rear wheel to skid. Perhaps that's
all the force you'd ever need, but I'm doubtful.

Your questions are why I started this thread. I hoped there was
someone out there with some experience with it or something similar.
I would like to try the system out, but I don't know if I'm up to
building it myself. As far as the front wheel braking force, it is
adjustable, but I don't know if there would be a best ratio. It is
probably dependent on conditions. That is one obvious draw back.

Max

Max said:

[email hidden] (Gary Young) wrote in message news:<[email hidden]>...

Quoted message said:

Yes, but how do you get out of the skid except by letting up on the
rear brake? With this system, letting up on the rear brake means no
front brake either. What happens in a panic stop when you when you
have to use the front brake? Your front braking can be no more
forceful than what would cause the rear wheel to skid. Perhaps that's
all the force you'd ever need, but I'm doubtful.

Your questions are why I started this thread. I hoped there was
someone out there with some experience with it or something similar.
I would like to try the system out, but I don't know if I'm up to
building it myself. As far as the front wheel braking force, it is
adjustable, but I don't know if there would be a best ratio. It is
probably dependent on conditions. That is one obvious draw back.

Yes, the two main drawbacks I see are 1) that there is no redundancy
(failure of the rear cable or brake mechanism leaves you with no braking
at all), and 2) that you lose individual control over the brakes which
may be critical on loose surfaces. The loss of individual control would
also be a problem on long steep descents where you want to avoid
overheating either rim. I wouldn't want to rely on such a system
without installing a third, independent, brake controlled by a separate
lever.

A somewhat similar design was described in Bicycling! many years ago
(prob. late '70s). It was on a tandem with a rear drum brake and front
and rear caliper brakes. In that case the goal was to improve the
effectiveness of the rear braking by using the reaction arm of the drum
brake to pull the cable of the rear caliber brake. By adjusting the
length of the lever arm it was easy to adjust the amount of force
multiplication generated by this "power-brake" system. But the same
design could be used to have a rear drum brake actuate the front brake
as in the Calderazzo design and I think this would be easier to
construct than the sliding rear brake mount shown in your referenced
figure.

The Calderazzo design has a different goal - namely to let the rider
apply as much front braking force as possible without any fear of
lifting the rear wheel off the ground. The test reports were that it
was very successful at that in tests of panic stops. The testing was
finally ended when the repeated hard front braking resulted in a cracked
front fork.

Max Lehman said:

Quoted message said:

Quoted message said:

Has anyone seen or used something like the Calderazzo feedback
brake system? It has the rear brake on a spring mounting that
actuates the front brake while braking. So you only need one
brake lever and it will stop front braking if the rear wheel
leaves the ground. It looks like this:

http://www.thelehmans.net/temp/calderazzo_brakes.gif

Quoted message said:

Quoted message said:

Quoted message said:

from Bicycling Science.

Quoted message said:

Quoted message said:

Could you give a link to an explanation of the value of this brake?
Mention of releasing the front brake if the rear wheel leaves the
ground implies that it is designed to prevent people from "going
over the bars". People who go over the bars do not brake hard
enough to raise the rear wheel anyway so this is an illusion.

http://draco.acs.uci.edu/rbfaq/FAQ/9.36.html

Quoted message said:

Quoted message said:

How does Bicycling Science fit into this? This isn't science and
as far as I can see, it doesn't exist in hardware. Can you fill in
some blanks?

Quoted message said:

I don't have a link to an explanation. The image was scanned from
the book Bicycling Science (third edition) by David Gordon Wilson
and is discussed from page 255.

Oh, then this is the same brake as the one that was discussed a long
time ago. Does it exist and is there a photograph of one?

Quoted message said:

There were 2 main advantages discussed: (1)if you do start to tip
forward, the front brake will release just long enough to bring the
rear wheel back down and (2) you could use this method to apply "any
reasonable degree of force multiplication." So you could even
actuate a coaster brake in the front wheel.

Well, as I explained, people who "go over the bars" do not brake hard
and therefore this would do them no good except to offer a security
blanket with holes. I have challenged people, who claim to have
braked so hard their bicycle overturned, to just raise the rear wheel
in the parking lot of the bicycle shop. They did not succeed. That
doesn't mean they realized that the bicycle overturned when their legs
hit the bars as they launched themselves from the bicycle... even
though I tried to explain that to them.

Quoted message said:

I agree that going over the handlebars would be a rare event for an
experienced rider, but not unheard of, specially on steep hills.

I don't think you understand the concept. Raising the rear wheel
required significant force before the advent of the dual pivot (high
mechanical advantage) brake. Riders, regardless of slope require
substantial front wheel braking to raise the rear wheel. Therefore,
an inexperienced rider would not have this problem because, as I
explained, they are not capable of braking hard enough to raise the
rear wheel. That this appears in Bicycling Science, along with other
inane lore is more proof that the writers either forgot about or never
were young hot-rod racers who did all these things. As you see, one
can construct them in the minds eye, but these visualizations are
flawed.

Quoted message said:

And I agree that it isn't manufactured. I posted this looking for
someone who had tried something similar, or even built their own.

I doubt that anyone has because it is not reasonably possible to
construct such a device. It only works in diagram form with liberal
interpretation. That's why I would like to see a working unit to
assess its mechanical abilities. I am sure that could not be done,
judging from my experience in designing such mechanisms.

Quoted message said:

Hope that helps a little,

Not much. This is well tilled soil.

Jobst Brandt
[email hidden]

Quoted message said:

...Riders, regardless of slope require
substantial front wheel braking to raise the rear wheel....

The above may be true on any reasonable roadway, but there are
situations where even a slight braking force on the front wheel will
raise the rear wheel. I am aware of concrete drainage channels that have
a greater than 1:1 slope, and have seen people ride bicycles down them.
I have also ridden [1] through dry ravines off road that were steeper
than a 2H: 1V slope.

[1] And crashed into a tree on the far side. 🙁

--
Tom Sherman

Tom Sherman said:

Quoted message said:

...Riders, regardless of slope require substantial front wheel
braking to raise the rear wheel...

Quoted message said:

The above may be true on any reasonable road, but there are
situations where even a slight braking force on the front wheel will
raise the rear wheel. I am aware of concrete drainage channels that
have a greater than 1:1 slope, and have seen people ride bicycles
down them. I have also ridden [1] through dry ravines off road that
were steeper than a 2H: 1V slope.

Quoted message said:

[1] And crashed into a tree on the far side. 🙁

I guess you haven't been to a circus lately where stunt riders do
unbelievable gymnastics with bicycles, riding on walls and balancing
on front wheels. People who go over the bars don't do that and riding
down more than a 50% grade is risky foolishness right from the start.
We have a spillway in Los Gatos with 40 degree concrete walls. Two
MTB riders thought it would be clever to ride parallel to the trail
on the top by traversing this clean concrete wall. I last saw them
swimming in the creek trying to retrieve their bicycles 20 feet below
the trail.

So? That has little to do with the Calderazzo feedback brake system.

Jobst Brandt
[email hidden]

Quoted message said:

Tom Sherman said:

Quoted message said:

...Riders, regardless of slope require substantial front wheel
braking to raise the rear wheel...

Quoted message said:

The above may be true on any reasonable road, but there are
situations where even a slight braking force on the front wheel will
raise the rear wheel. I am aware of concrete drainage channels that
have a greater than 1:1 slope, and have seen people ride bicycles
down them. I have also ridden [1] through dry ravines off road that
were steeper than a 2H: 1V slope.

Quoted message said:

[1] And crashed into a tree on the far side. 🙁

I guess you haven't been to a circus lately where stunt riders do
unbelievable gymnastics with bicycles, riding on walls and balancing
on front wheels...

I have seen BMX freestyle riders successfully complete maneuvers that
most people could not even come close to doing, so I have a pretty good
idea what is possible with the right combination of talent and practice.

Quoted message said:

People who go over the bars don't do that and riding
down more than a 50% grade is risky foolishness right from the start....

No argument there. 🙂

Quoted message said:

We have a spillway in Los Gatos with 40 degree concrete walls. Two
MTB riders thought it would be clever to ride parallel to the trail
on the top by traversing this clean concrete wall. I last saw them
swimming in the creek trying to retrieve their bicycles 20 feet below
the trail.

So? That has little to do with the Calderazzo feedback brake system...

I was being pedantic. 😉

--
Tom Sherman