Tech
cont’d
To make sure that you have maximum friction available, keep your
wheel rims and brake pads or the disc rotor and caliper clean and
free of dirt, lubricants, waxes or polishes.
Brakes are designed to control your speed, not just 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 to begin to lock up, release pressure just a little
to keep the wheel rotating just short of lock up. Its 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 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. 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.
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. How a Derailleur Drivetrain Works
If your bicycle has a derailleur drivetrain, the gear-changing mechanism will have:
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