Braking Technique

warren wrote:

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

Uh, no. Because if the rear wheel still has significant traction,
you aren't applying enough front brake.

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.

In situations like Beloki's, it isn't clear to me what the proper strategy
would have been, I wasn't there and I don't know what the road looked like
in terms of bumps, camber, or traction.

I disagree with some people when viewing the video. It's clear to me he
locked up the rear wheel to set the slide in motion, which kicked the wheel
out to his left. So he was using too much rear brake. Maybe he hit
an especially slippery spot that helped break it loose. But still - too much
rear brake. Some pepole might say that he was just using the front,
and he used it so much that the rear was "light", and so it slipped to
the left because of the tar, camber, or him starting to lean for the turn.
That's possible. Maybe Beloki will remember and can tell us.

Now, this is easy to say in hindsite, sitting at my computer, but. . .
When the wheel slipped to his left, I think it would have been better for
him to release both brakes to regain traction and then dive into the turn
and hope for the best. He either would have low sided, with less injuries,
or run off the road like Lance. But instead he continued to brake, maybe
with just the front, his rear wheel appeared to come up, and then swung to
the right. When it landed he was pointing in the wrong direction for the
turn, the tire came off, he high sided. Even if the tire didn't blow or come
off the rim he was in no position to make the turn.

So, to summarize, I think poor use of the rear brake set the rear sliding,
and then poor management of the slide led to the actual crash. He was
coming in way too hot for that turn, which probably led him to lean on the rear
brake too much.

In article , BikeRacer
wrote:

warren wrote:

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



Uh, no. Because if the rear wheel still has significant traction,
you aren't applying enough front brake.

This is a ridiculous statement!


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. Period. You also push your weight
back a bit to put more weight on the rear wheel so it grabs/adheres to
the pavement better. This allows for more braking power. Period.

So, to summarize, I think poor use of the rear brake set the rear sliding,

#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.

He was
coming in way too hot for that turn, which probably led him to lean on the rear
brake too much.

It's a very fine line between too much braking on one wheel or the
other and just enough.

#2) Tell us, in this precarious situation, and knowing that if you hit
some slick or loose road surface a wheel with even a tiny amount of
braking could slip, which wheel would you rather apply just a little
too much brake to?

#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?

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.

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

-WG

Lance isn't nearly as great a rider as you are.

"asqui" wrote in message
...
In the footage of Beloki's spectacular crash it can be seen that
Armstrong
briefly locks up his rear wheel as Beloki crashes. I thought on a
decent
surface the best way to stop was front brake only? I guess that was
feasible
with the Weinmann brakes on my Eddy Meckx but these Tektro
cantilevers leave
some braking performance to be desired . Anyway, obviously on a
descent
like that you'll want to use both to distribute the rim heating
evenly, but
why did Lance lock up the rear? In the emergency situation shouldn't
he have
been using the front brake exclusively -- exactly for the reason of
avoiding
a rear wheel skid?

(I will agree that front brake only is a little "eggs in one basket"
because
if you wash out the front you're pretty much gone, but I'm arguing
based on
the "front brake only" rule I've heard time and time again.)

Dani

"Carl Sundquist" wrote in message
...

"S. Anderson" wrote in message

Incidentally, I hit the racetrack every now and again with my
motorcycle
and
I NEVER touch the rear brake when at the track. However, if you
watch the
good guys, you can see them sliding the rear tire into corners
using the
rear brake and engine braking. These guys are able to decode the
input
from
the bike to do those things. I'm simply overwhelmed with all the
stuff
going on and cannot do the stuff they do. So your idea of
front-brake
only
may be analogous to my motorcycle situation..if you can't reliably
operate
the rear brake during max braking so that the rear wheel doesn't
skid,
you're probably better off using the front only.


Take one XR-100, add one steel shoe, mix in a dirt field and you'll
learn
wonders.

Carl
Proud attendee
Kenny Roberts Training Ranch

BS

Tom
Kenny Roberts was a jr. when I was racing.

"Tom Kunich" wrote in message

Take one XR-100, add one steel shoe, mix in a dirt field and you'll
learn
wonders.

Carl
Proud attendee
Kenny Roberts Training Ranch

BS

Tom
Kenny Roberts was a jr. when I was racing.



What the hell are you talking about?

"asqui" wrote in message
...

What about leaning your weight? I have seen that other people can rather
competently steer a bike with their hands off the bars. Not through any
hairpins mind you.


Leaning produces the same effect as countersteering. You shift your weight
and start the bike falling over, which is exactly what countersteering does.
But once the lean is initiated, the wheel turns into the direction of the
turn, maintaining an equilibrium which allows you to maintain the turn.
Conciously countersteering just makes the whole thing happen a lot faster,
which allows you to negotiate those hairpins at speed, something you can't
easily do with no-hands. The mechanism of the countersteer occurs any time
a lean angle is introduced into the equation..whether the source is obvious
or not so obvious, it's still there.

Cheers,

Scott..

In article k.net,
Tom Kunich wrote:

Lance isn't nearly as great a rider as you are.

But, but Tom, he read it on the internet and his buddies confirmed it!
It must be true!

-WG




"asqui" wrote in message
...
In the footage of Beloki's spectacular crash it can be seen that
Armstrong
briefly locks up his rear wheel as Beloki crashes. I thought on a
decent
surface the best way to stop was front brake only? I guess that was
feasible
with the Weinmann brakes on my Eddy Meckx but these Tektro
cantilevers leave
some braking performance to be desired . Anyway, obviously on a
descent
like that you'll want to use both to distribute the rim heating
evenly, but
why did Lance lock up the rear? In the emergency situation shouldn't
he have
been using the front brake exclusively -- exactly for the reason of
avoiding
a rear wheel skid?

(I will agree that front brake only is a little "eggs in one basket"
because
if you wash out the front you're pretty much gone, but I'm arguing
based on
the "front brake only" rule I've heard time and time again.)

Dani

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. Motorcyclists
can, which leads them into all kinds of body contortions to get their
bikes more upright.

Motorbikes can also put on power anytime they want, which notably
changes their handling in corners relative to bicycles.

--
Ryan Cousineau, http://www.sfu.ca/~rcousine
President, Fabrizio Mazzoleni Fan Club

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. 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.

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.


You also push your weight
back a bit to put more weight on the rear wheel so it grabs/adheres to
the pavement better. This allows for more braking power.

Moving weight rearward increases the maximum braking limit -
but not because it gives more rear wheel traction. The
reason is because it increase the limit of braking before
the pitch over point. None-the-less, it is a relatively
small affect, because a cyclist can move their center of
gravity back by no more than a few inches.



So, to summarize, I think poor use of the rear brake set the rear sliding,


#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.


#2) Tell us, in this precarious situation, and knowing that if you hit
some slick or loose road surface a wheel with even a tiny amount of
braking could slip, which wheel would you rather apply just a little
too much brake to?

Obvious the rear. Under low traction situations, the
braking limit of both wheels is limited, but with the
forward weight shift, the front wheel still has more
traction available for braking, so much of the braking can
still be done with the front wheel, and it is still possible
to over brake the rear.

#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. The rear brake is there as a back-up, and for
situations of less than ideal traction.

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.

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). But if you were getting any significant rear wheel
traction, you were below that limit, and your stopping
distance would have been further still. Perhaps you should
re-evaluate your perception of your braking ability.


#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. Good braking technique is required for many
types of riding, not just criteriums of "Cat 3 or higher".
For example, descending on steep, twisty roads - and many
"fatty masters" can descend faster many cat 3 (and higher)
racers, simply because of their extra mass/frontal area ratio.



Mark McMaster

Mark McMaster wrote:

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

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.

Explain this: If you are anywhere near zero traction on the rear,
what would keep you from pivoting around and essentially crashing
as Beloki did? Seems to me that was Beloki's problem, exacerbated
by the fact that the road surface where his back wheel was was
slicker than the front producing near-zero traction at less than
tipping g's. Seems you must keep enough traction to keep from
going sideways in the rear.