Braking Technique

"asqui" wrote in message ...
warren wrote:
I think you should worry less about invalid "arguments" and spend the
time practicing with both brakes and keeping your weight farther back
under heavy braking. Don't you think that having two tires making
contact/friction with the ground would work better?

-WG

So yeah... now that I found out where I read this invalid argument perhaps
you would like to consult the rec.bicycles.* faq around he
http://draco.acs.uci.edu/rbfaq/FAQ/9.17.html
Eating one's hat is optional.

Dani

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

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

Peter

warren wrote in message ...
In article , asqui
wrote:

Andrew Lee wrote:
"asqui" wrote

warren wrote:
I think you should worry less about invalid "arguments" and spend
the time practicing with both brakes and keeping your weight
farther back under heavy braking. Don't you think that having two
tires making contact/friction with the ground would work better?

-WG

So yeah... now that I found out where I read this invalid argument
perhaps you would like to consult the rec.bicycles.* faq around he
http://draco.acs.uci.edu/rbfaq/FAQ/9.17.html
Eating one's hat is optional.

Try reading this: http://draco.acs.uci.edu/rbfaq/FAQ/9.15.html

This has more information about braking in the context of corners...

Sorry, perhaps I wasn't clear in my original post. I was referring to
emergency braking on a good surface in a straight line. Armstrong was
braking in a straight line as he came past the outside of Beloki. This
section of the faq states once more that front brake only is the quickest
way to decelerate as long as you're not banked in the middle of a turn.

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

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

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

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

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

Peter

warren wrote:
In article , Mark McMaster
wrote:

warren wrote:
In article ,
BikeRacer wrote:


warren wrote:

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

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


You'd have more control and reduce speed quicker with some braking
applied to the rear wheel than none.

That defies the laws of physics.

Read what I said. "You'd have more control..."

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

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

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

Shift your weight back. AND I can steer without too much worry about
the front wheel locking up. We're talking about racing here, not your
ideal application of theories.

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

On a typical road bike, the limit of braking with the front
brake alone is about 1/2 g. The limit of braking with the
rear brake along is about 1/4 g. Using both brakes, the
limit is between these two.

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

Ridiculous!

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

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

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

You didn't answer the question. "How do you get the rear wheel to go
to
the side...?" And you are forgetting the all important ability to
steer predictably.

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

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

There is strong argument that the rear brake is not required
at all when stopping in a straight line on clean dry
pavement.

Sure. Tell that to the guys who race for a living. You should do the
comedy circuit because you've got some hilarious mateerial here!

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

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

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

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

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

Your braking example is interesting one (28mph to 5mph in 30
feet). Not because it shows your mastery of braking, but
because it shows your poor estimation of your braking
capacity. Going from 28mph to 5mph in 30 feet on a standard
upright bicycle is essentially impossible. It would require
a uniform deceleration rate of 0.85 g, impossible to achieve
on an upright racing bike. Deceleration from 28 mph to 5
mph would take a minimum of 50 feet at the limit of braking
(1/2g).

There was a very slight uphill, and perhaps I was still going 6.2 mph
when I made impact. My computer showed 28-5. And how can you calculate
my stopping time or distance if you don't know what tire compound I
use, the inflation of the tires, the size of the contact patch, my
amount of weight shift, the road surface or grade, etc.? You don't
even
know what you don't know.

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

An interesting question, but completely irrelevant to the
discussion.

No it's not. It's guys just like you with all their theories who do
not
fully understand the real world application of those theories simply
because you lack enough real world experience to make an accurate
assessment.

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

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

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

-WG

In article , asqui
wrote:

warren wrote:
In article , Mark McMaster
wrote:

warren wrote:
In article ,
BikeRacer wrote:


warren wrote:

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

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


You'd have more control and reduce speed quicker with some braking
applied to the rear wheel than none.

That defies the laws of physics.

Read what I said. "You'd have more control..."

No, you said "You'd have more control and reduce speed quicker...". The
paragraph quoted immediately below states that the maximal deceleration is
at the pitch-over point where rear braking provides little to no
deceleration.

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

You didn't answer the question. "How do you get the rear wheel to go
to
the side...?" And you are forgetting the all important ability to
steer predictably.

On a steep decent with heavy braking on the front and a locked up rear, the
friction between the rear tyre and the ground is pretty close to zero.

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


There is strong argument that the rear brake is not required
at all when stopping in a straight line on clean dry
pavement.

Sure. Tell that to the guys who race for a living. You should do the
comedy circuit because you've got some hilarious material here!

There is no reason to resort to personal insults.

This guy is silly. His ridiculous comments deserve ridicule.

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

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

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

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

An interesting question, but completely irrelevant to the
discussion.

No it's not. It's guys just like you with all their theories who do
not
fully understand the real world application of those theories simply
because you lack enough real world experience to make an accurate
assessment.

If the application of the theories is not as expected in the real world then
you need to provide reasons for this, not just fall back on your experience.

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

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

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


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

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

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

-WG

warren wrote:
In article , asqui
wrote:

warren wrote:
In article , Mark McMaster
wrote:

warren wrote:
In article ,
BikeRacer wrote:


warren wrote:

On a steep decent with heavy braking on the front and a locked up
rear, the friction between the rear tyre and the ground is pretty
close to zero.

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

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

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

There is no reason to resort to personal insults.

This guy is silly. His ridiculous comments deserve ridicule.

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

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

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

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


If the application of the theories is not as expected in the real
world then you need to provide reasons for this, not just fall back
on your experience.

No I don't need to know, or argue the understandings of physics. I need
to know what actually works in a bike race, and I don't always care
about or need to know the physics of why things work the way they do.

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

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

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

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


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

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

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


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

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

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

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

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

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

Dani

warren wrote:
In article , Mark McMaster
wrote:


warren wrote:

You'd have more control and reduce speed quicker with some braking
applied to the rear wheel than none.

That defies the laws of physics.


Read what I said. "You'd have more control..."

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


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


Ridiculous!

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



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

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


You didn't answer the question. "How do you get the rear wheel to go to
the side...?" And you are forgetting the all important ability to steer
predictably.

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




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

There is strong argument that the rear brake is not required
at all when stopping in a straight line on clean dry
pavement.


Sure. Tell that to the guys who race for a living.

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

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

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

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

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

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


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

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



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


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


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



Your braking example is interesting one (28mph to 5mph in 30
feet). Not because it shows your mastery of braking, but
because it shows your poor estimation of your braking
capacity. Going from 28mph to 5mph in 30 feet on a standard
upright bicycle is essentially impossible. It would require
a uniform deceleration rate of 0.85 g, impossible to achieve
on an upright racing bike. Deceleration from 28 mph to 5
mph would take a minimum of 50 feet at the limit of braking
(1/2g).


There was a very slight uphill, and perhaps I was still going 6.2 mph
when I made impact.

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


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

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

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

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



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

An interesting question, but completely irrelevant to the
discussion.


No it's not. It's guys just like you with all their theories who do not
fully understand the real world application of those theories simply
because you lack enough real world experience to make an accurate
assessment.

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



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

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

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


Mark McMaster

"Ryan Cousineau" wrote in message
...
In article ,
"Kurgan Gringioni" wrote:

"BikeRacer" wrote in message
m...
warren wrote:

When it comes to turning, motorcycles diverge from bicycles somewhat
because of the engine. . .

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

If cyclists get away with that, it's because they will never run out of
ground clearance before they run off the edge of the tire.



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

In article , asqui
wrote:

warren wrote:
In article , asqui
wrote:

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

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

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

If the application of the theories is not as expected in the real
world then you need to provide reasons for this, not just fall back
on your experience.

No I don't need to know, or argue the understandings of physics. I need
to know what actually works in a bike race, and I don't always care
about or need to know the physics of why things work the way they do.

Well, then your input is going to be of little value to this discussion if
you are unable to translate what you experience in the real world of bike
racing to the world of physics. "According to physics, this happens,
therefore A."

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

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


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

Somewhere close to 700, and one more today.

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

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

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

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

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

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

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

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

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

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

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

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

Considering we are talking strictly about braking in a straight line on a
good, level, dry surface, throwing something in my path would be entirely
innapropriate.

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

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

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

-WG

In article , Mark McMaster
wrote:

warren wrote:
In article , Mark McMaster
wrote:


warren wrote:

You'd have more control and reduce speed quicker with some braking
applied to the rear wheel than none.

That defies the laws of physics.


Read what I said. "You'd have more control..."

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

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


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

There is strong argument that the rear brake is not required
at all when stopping in a straight line on clean dry
pavement.


Sure. Tell that to the guys who race for a living.

Someone has already be beaten me to it.

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

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

Not nearly as comedic as your continual scoffing despite not
having evidence to support your position,

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

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


Why couldn't you steer with more front brake?

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

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

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

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

An interesting question, but completely irrelevant to the
discussion.


No it's not. It's guys just like you with all their theories who do not
fully understand the real world application of those theories simply
because you lack enough real world experience to make an accurate
assessment.

Just how do you know how much real world experience I may or
may not have?

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

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

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

Evasive as usual.

-WG

warren wrote:
In article , Mark McMaster
wrote:


warren wrote:

Read what I said. "You'd have more control..."

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


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

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


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

There is strong argument that the rear brake is not required
at all when stopping in a straight line on clean dry
pavement.


Sure. Tell that to the guys who race for a living.

Someone has already be beaten me to it.


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

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


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

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

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

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

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


Why couldn't you steer with more front brake?


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

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


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


I guess my eyes have deceived me when I saw it happen all those times.

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


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



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

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

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


Just how do you know how much real world experience I may or
may not have?


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

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



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

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


Evasive as usual.


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


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

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


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


Mark McMaster