Jamis Bicycle Owner's Manual - page 17
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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. It will take longer to stop 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.
1. Brake controls and features
It’s very important to your safety that you learn and remember which brake lever controls which brake on your bike.
Traditionally, the right brake lever controls the rear brake and the left brake lever controls the front brake; but, to
make sure your bike’s brakes are set up this way,
squeeze one brake lever and look to see which brake, front or rear,
engages. Now do the same with the other brake lever.
Make sure that your hands can reach and squeeze the brake levers comfortably. If your hands are too small to
operate the levers comfortably, consult your dealer before riding the bike. The lever reach may be adjustable; or you
may need a different brake lever design.
Most rim brakes have some form of quick-release mechanism to allow the brake pads to clear the tire when a wheel
is removed or reinstalled. When the brake quick release is in the open position, the brakes are inoperative. Ask your
dealer to make sure that you understand the way the brake quick release works on your bike (see figs. 12, 13. 14 & 15)
and check each time to make sure both brakes work correctly before you get on the bike.
2. How brakes work
The braking action of a bicycle is a function of the friction between the braking surfaces. To make sure that you have
maximum friction available, keep your wheel rims and brake pads or the disk rotor and caliper clean and free of dirt,
lubricants, waxes or polishes.
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.