Giant - V8.0, Руководство пользователя

Страница: 25 / 46

25
Everything changes when you ride 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 to begin with.
!
D. Shifting gears
!
Your multi-speed bicycle will have a derailleur drivetrain (see 2. below), an internal gear hub drivetrain (see
3. 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:
!
• 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
a. Shifting Gears
!
There are several different types and styles of shifting controls: levers, twist grips, triggers, combination
shift/brake controls and push-buttons. Ask your dealer to explain the type of shifting controls that are on your
bike, and to show you how they work.
!
The vocabulary of shifting can be pretty confusing. A downshift is a shift to a “lower” or “slower” gear, one
which is easier to pedal. An upshift is a shift to a “higher” or “faster”, harder to pedal gear. What’s confusing
is that what’s happening at the front derailleur is the opposite of what’s happening at the rear derailleur (for
details, read the instructions on Shifting the Rear Derailleur and Shifting the Front Derailleur below). For
example, you can select a gear which will make pedaling easier on a hill (make a downshift) in one of two
ways: shift the chain down the gear “steps” to a smaller gear at the front, or up the gear “steps” to a larger
gear at the rear. So, at the rear gear cluster, what is called a downshift looks like an upshift. The way to keep
things straight is to remember that shifting the chain in towards the centerline of the bike is for accelerating
and climbing and is called a downshift. Moving the chain out or away from the centerline of the bike is for
speed and is called an upshift.
Whether upshifting or downshifting, the bicycle derailleur system design requires that the drive chain be
moving forward and be under at least some tension. A derailleur will shift only if you are pedaling forward.
CAUTION: Never move the shifter while pedaling backward, nor pedal backwards immediately
after having moved the shifter. This could jam the chain and cause serious damage to the bicycle.