28
29
PART I
(continued from previous page...)
Brakes are designed to control your speed, not just
to stop the bike. Maximum braking force for each
wheel occurs at the point just before the wheel
“locks up” (stops rotating) and starts to skid. Once
the tire skids, you actually lose most of your stopping
force and all directional control. You need to practice
slowing and stopping smoothly without locking up
a wheel. The technique is called progressive brake
modulation. Instead of jerking the brake lever to the
position where you think you’ll generate appropriate
braking force, squeeze the lever, progressively
increasing the braking force. If you feel the wheel
begin to lock up, release pressure just a little to keep
the wheel rotating just short of lockup.
It’s important to develop a feel for the amount
of brake lever pressure required for each wheel at
different speeds and on different surfaces. To better
understand this, experiment a little by walking your
bike and applying different amounts of pressure to
each brake lever, until the wheel locks.
When you apply one or both brakes, the bike begins
to slow, but your body wants to continue at the
speed at which it was going. This causes a transfer
of weight to the front wheel (or, under heavy braking,
around the front wheel hub, which could send you
flying over the handlebars).
A wheel with more weight on it will accept greater
brake pressure before lockup; a wheel with less
weight will lock up with less brake pressure. So,
as you apply brakes and your weight is transferred
forward, you need to shift your body toward the
rear of the bike, to transfer weight back on to the
rear wheel; and at the same time, you need to both
decrease rear braking and increase front braking
force. This is even more important on descents,
because descents shift weight forward.
Two keys to effective speed control and safe stopping
are controlling wheel lockup and weight transfer.
This weight transfer is even more pronounced if your
bike has a front suspension fork. Front suspension
“dips” under braking, increasing the weight transfer
(see also SECTION 4.F). Practice braking and weight
transfer techniques where there is no traffic or other
hazards and distractions.
Everything changes when you ride on loose surfaces
or in wet weather. Tire adhesion is reduced, so the
wheels have less cornering and braking traction and
can lock up with less brake force. Moisture or dirt on
the brake pads reduces their ability to grip. The way
to maintain control on loose or wet surfaces is to go
more slowly.
More info:
ROAD BIKES: DISC BRAKES
Now, go to PART II of this manual
and read “Understanding Disc Brakes
on Road Bikes”
