Brakes
Their Real Job Is NOT
To Stop
- it is to SLOW the bike
For
some reason most motorcyclists seem to think that the job of brakes is
to stop their motorcycles. Wrong!
If all
the brakes had to do was stop you then all they would have to do is
lock your wheels when you applied them - clearly not an optimum use of
their enormous power. Indeed, from a safety point of view more often
than not your challenge when using your brakes, particularly the rear
brake, is to prevent the wheel from stopping (locking)!
By far
the most important job of your brakes is to SLOW you down. In other
words, your brakes are a negative accelerator. Unlike your throttle,
you can vary your speed all the way from the bike's top speed to zero
without having to shift gears - in less time than it
took to get from zero to that top speed. This demonstrates pretty
easily that they are far more powerful than your engine. Yet if used
properly, they can be just as subtle in controlling speed as your
throttle and clutch combined.
Since
you can generate nearly 100% of your stopping power with the front
brake on almost any contemporary motorcycle (meaning that you can
reduce traction of the rear wheel to zero via load shifting), there is
a pretty strong argument that can be made that you should focus your
entire braking attention to the task of using it and ignoring the fact
that you even have a rear brake. I would not go that far, however.
If you need to stop or slow down on slick or gravel surfaces, the
rear brake is just the ticket (in combination with a very gentle
hand on the front one.)
In very slow maneuvers, the use of the rear brake alone often
provides added stability and control of your motorcycle.
The
most dangerous control you have on your motorcycle is your rear brake!
This, because it is easy to STOP (your rear wheel) with it. A spinning
rear wheel is what provides the majority of your bike's stability. The
gyroscopic effect of a spinning rear wheel is imposed on the frame of
the motorcycle and determines the attitude/stability of the entire
bike except for its relatively insignificant front-end. To lock the
rear wheel is, by definition, to remove the majority of your attitude
control and stability.
For
this reason I am amazed that the MSF continues to provide a field
exercise ('Controlling a rear wheel skid') to its students that
invites them to harshly activate their rear brake only and skid to a
stop. [Any bike that has integrated braking in any form is not
required to do this exercise at all.] Surviving a rear brake lock at
the modest speeds used in the exercise (less than 20 MPH) may well
lead some students to the mistaken conclusion that they can recover
from same at any speed. Still, the MSF goes out of its way to tell
their students that use of the rear brake only is NOT a normal or
recommended stopping proceedure - but they fail to explain why not.
Yet
another exercise they have the students perform is to stop (without
locking the wheel) by using only their rear brake. This is one of
three exercises designed to demonstrate that the use of both brakes at
the same time is more efficient than using either one alone. It would
be entirely sufficient to show how using both brakes together is more
efficient than using the front brake alone. The first part of the
exercise, which has the students apply their rear brakes only (but not
so aggressively that they lock them), is simply too easy for a newbie
to misunderstand to be just one more reasonable habit to develop -
after all, "the MSF showed us how to do it."
During
a panic situation your attention must be directed to the aggressive
use of your front brake and at that time heavy application of the rear
brake will almost certainly result in loss of control.
There
is NEVER a time while riding a motorcycle that harsh use of the rear
brake is anything but dangerous and wrong-headed.
And
while harsh use of the rear brake, ever, is dangerous,
there is one thing that is dumber still - using your engine to
'assist' during a panic stop. Your engine is NOT A BRAKE! Further, it
only affects the rear wheel which we have already seen is easily
stopped (locked) with even modest rear brake usage by itself. (In
other words, during a panic stop situation you want your
clutch fully disengaged. In no way is this to be taken as a suggestion
not to use normal engine braking resulting from throttle roll-off.)
Use
of the rear brake requires a gentle, controlled touch - EVERY TIME!
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