Operation Manual
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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 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.
D. Shifting gears
Your multi-speed bicycle will have a derailleur drivetrain (see 1. below),
an internal gear hub drivetrain (see 2. below) or, in some special cases, a
combination of the two.
1.Howaderailleurdrivetrainworks
If your bicycle has a derailleur drivetrain, the gear-changing mechanism will
have:
• a rear cassette or freewheel sprocket cluster
• a rear derailleur
• usually a front derailleur
• one or two shifters
• one, two or three front sprockets called chainrings
• a drive chain