Re: Thoughts on braking

[E & V Willson]

As one who has ridden both a bike and motorcycle, let me tell you that
only using the rear brake is near suicide. When the rear brake locks up,
the friction (stopping) force drops to near zero. What this means is that
there is less resistance from the locked (skidding) rear wheel than from
the rolling front wheel. As a consequence the rear wheel will come around
bringing you into a classic sideways skid. I know this unfortunate
experience. On the other hand if you brake hard on the front wheel, the
rear will just roll behind it, keeping in a straight line (assuming you do
not brake hard enough to endo).

If there was a choice between braking with the rear wheel or the front,
the front is the answer. The correct move is to first apply the front,
followed rapidly by the rear. Control the pressure on each brake so as to
prevent wheel lock, and stop in a straight line. Don't forget that a
locked wheel provides no gyroscopic force to keep you upright.
HTH.
Ernie

Luigi de Guzman wrote:

> So i've got to get to the library and return books. Somewhere in the
> middle of the City, in crowded stop-and-go traffic, my front brake
> cable snaps. apply my rear coaster brake (yuk). Limp to the library,
> return books, get bike to shop where a shopdude fits me up with new
> cable for GBP 1.80. great.
>
> I observe from my brief trip without a front brake that I am more or
> less utterly dependent on it. it's very hard for me to imagine riding
> without one. And yet when I got back to my room, I had an interesting
> AIM conversation with a friend fo mine from home:
>
> "you mean you use your *front* brake?" he said, somewhat incredulous.
> "I never use my front brake."
>
> I explain all the usual things--quote sheldon brown and my own
> experience, tell him to watch the beloki crash film again. but he
> persists. "Besides, all of my riding has been trail-riding, and I
> hardly ever use my front brake there."
>
> A statement I found very hard to believe.
>
> Then, out of curiosity, I went to see what our fossil-fueled brothers
> on motorbikes have to say about braking. They say to brake with both
> at the same time:
>
> "Use both brakes whenever slowing or stopping
>
> To stop, the hands and feet work together in a coordinated and smooth
> fashion. Squeeze the clutch and the front brake lever while pressing
> on the rear brake pedal and downshifting to first gear. The front
> brake provides around 70% of the stopping power for your motorcycle.
>
> Both brakes should be applied at the same time when stopping. Even
> though the full braking potential of each wheel may not be required
> for normal, planned stops, it is important to develop the habit of
> using both brakes so that your reflexes will be ready to respond
> quickly and properly when an emergency situation occurs."
>
> they even have a diagram:
>
> <http://www.msf-usa.org/CourseReview/assets/RiderHandbook_27_1.gif>
>
> In light of all of this I make a few observations & questions
>
> 1) Those big Flying Pigeons or Dutch roadsters, with only coaster
> brakes, were probably never intended to go very fast at all. My
> braking distance with only a rear coaster was scary, and my ability to
> brake depended largely on where my feet were in the pedal stroke.
> unnerving. [and I'm not very fast--the messengers and a lot of
> commuters, indeed, at at least one little girl can all beat me,
> speedwise]
>
> 2) Is there some sort of maximum speed, or some other purely physical
> limit to front-brake only braking? Why do the motorcycle guys
> recommend two-brake braking? [this will probably require me to do
> some tests when I go home, with the assistance of my science-minded
> younger brother]
>
> 3) If trail riders don't use their front brakes much--as my friend,
> who was a sometime MTBer, seems to allege--why do I see so many
> front-wheel disk brakes?
>
> -Luigi

[Werehatrack]

On Sat, 02 Aug 2003 05:25:57 GMT, "Phil, Squid-in-Training" >
may have said:

>> If there was a choice between braking with the rear wheel or the front,
>> the front is the answer. The correct move is to first apply the front,
>> followed rapidly by the rear. Control the pressure on each brake so as to
>
>Other way around. Braking the rear causes the (full) suspension on a road
>moto to settle, lengthening the wheelbase and lowering the CG. Then apply
>the front.

This also initiates the forward load transfer, increasing the traction
of the front wheel so that when the front brake applies, it is less
likely to lock.

I've been unsurprised that the cheapo suspension fork on my latest
low-budget acquisition can be easily bottomed by brake application.

--
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pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.

[John Henderson]

"Phil, Squid-in-Training" wrote:

> Other way around. Braking the rear causes the (full)
> suspension on a road moto to settle, lengthening the wheelbase
> and lowering the CG. Then apply the front.

Agreeing with you, I always hit the rear brake first with a
conventional bicycle too. If I require moderate to hard braking
force, I apply the front brake a fraction of a second later,
easing off the rear brake as I do so. In that time, the hard jab
on the rear brake has tested the adhesion, giving vital
information about how the front might behave. Any short rear
skid becomes easily felt, and generally causes me no loss of
stability.

The advantage is that this procedure soon becomes both quite
subtle and fully automatic, and I find the developed reflexes
quicker and more accurate than the mental pause otherwise
required to visually assess the surface before committing to
heavy front braking.

You can always hit a patch of slippery surface later in the
manoeuvre, so you've still got to keep your eyes open of course.

John

[Phil, Squid-in-Training]

> Agreeing with you, I always hit the rear brake first with a
> conventional bicycle too. If I require moderate to hard braking
> force, I apply the front brake a fraction of a second later,
> easing off the rear brake as I do so. In that time, the hard jab
> on the rear brake has tested the adhesion, giving vital
> information about how the front might behave. Any short rear
> skid becomes easily felt, and generally causes me no loss of
> stability.

Hmm... I never really thought about it the way you said it. Interesting to
note, however.

On my road (pedal-)bike I tend to use the rear exclusively for slow braking.
If I need to brake faster, or if something unexpected pops up in front of
me, I'll grab some of the front.

On the MTB at the trails, I'll brake with the front exclusively while
upright, going straight, and the rear mostly with a little of front while in
turns or technical stuff.

--
Phil, Squid-in-Training