Everything changes when you ride on loose surfaces or in wet
weather. Tyre adhesion is reduced, so the wheels have less
cornering traction and easily lock up when braking. 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) GEAR CHANGING
Your multi-speed bicycle will have either an external or internal
(inside the rear hub) gear change system.
1. OPEN GEAR CHANGE SYSTEM
The open gear change system includes the following:
• Cogset, referred to as a cassette or a freewheel depending
on the design
• Rear derailleur
• Front derailleur (optional)
• One or two shifters
• One, two, or three chain rings (front sprockets)
• Drive chain
A) How does the gear change work?
Various shifter designs are shown in figures 16–21.Before
reading on, find out what kind of shifters are installed on your
bicycle.
The vocabulary of shifting can be pretty confusing at first, but
we urge you to learn and fully understand the process.
Downshift is a shift to a lower, slower gear, one which is easier
to pedal. Up shift is a shift to a higher,
faster gear, one which is
harder to pedal. What’s
confusing is that what’s
happening at the front
derailleur is the opposite of
what’s happening at the
rear derailleur. For
example, you can select a
gear which will be easier to
pedal (make a downshift) in
two ways: put the chain to a
smaller chainring at the
front, or a larger sprocket at
the rear. To make it easier
to understand, just
remember that shifting the
chain to the inside, closer to
the bicycle centre line, is
downshifting, and shifting
the chain to the outside,
away from the bicycle
centre line is upshifting.
Both downshifting and
upshifting
work only when the drive chain is moving forward and under tension.
Moreover, derailleurs will only work when you are pedalling forward.
CAUTION: Never move the shifter when pedalling
backward, nor pedal backwards immediately after having moved
the shifter. This could jam the chain and cause serious damage
to the bicycle.
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