Tech 31
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 ying 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 trafc 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.
Adjusting the brakes
Your bicycle’s brakes have been correctly adjusted in the factory or by your dealer.
The gap between the brake block and the wheel rim is approx. 1 – 1.5 mm.
However, the brake blocks are subject to wear, so that the gap becomes ever
larger and the brake lever travel becomes longer. The brakes must therefore be
checked at regular intervals and adjusted if the lever travel is too great or the
brakes do not brake correctly.
Checking the brakes:
Pull the brake lever for the front or rear brake three quarters of the way back
whilst pushing the bicycle.
The rear wheel should lock, or
the front wheel should brake so strongly, that the bicycle begins to tip over
towards the front.
Adjusting the brake pad
Check if the brake pads are positioned in the center of the rim ank and do not
touch the tire when you pull the brake lever.
If they do not sit correctly, have them serviced by a dealer. To do it by yourself,
loosen the nut by a tting spanner or allen key. Replace the pads to a position as
shown. Retighten the nut to the correct torque, see page 45. Check the position
again. Repeat if nessecary.
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 gs. 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
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