Verso KC720-220, Руководство пользователя

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Tech
cont’d
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 A rear cassette or freewheel sprocket cluster
 A rear derailleur
 Usually a front derailleur
 One or two shifters
 One, two or three sprockets called chainrings
 A drivetrain
a. Shifting Gears
There are several different types of shifting controls: levers, twist grips, triggers,
combination shift/brake controls and push-buttons. Ask a certified bike mechanic 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). 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
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.
b. Shifting the Rear Derailleur
The rear derailleur is controlled by the right shifter.
The function of the rear derailleur is to move the drive chain from one gear
sprocket to another. The smaller sprockets on the gear cluster produce higher gear ratios.
Pedaling in the higher gears requires greater pedaling effort, but takes you a greater
distance with each revolution of the pedal cranks. The larger sprockets produce lower
gear ratios. Using them requires less pedaling effort, but takes you a shorter distance with
each pedal crank revolution. Moving the chain from a smaller sprocket of the gear cluster
to a larger sprocket results in a downshift. Moving the chain from a larger sprocket to a
smaller sprocket results in an upshift. In order for the derailleur to move the chain from
one sprocket to another, the rider must be pedaling forward.
c.
Shifting the Front Derailleur
The front derailleur, which is controlled by the left shifter, shifts the chain between
the larger and smaller chainrings. Shifting the chain onto a smaller chainring makes
pedaling easier (a downshift). Shifting to a larger chainring makes pedaling harder (an
upshift).
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.