Cannondale Bicycle Corp. 2000 OM Page 57
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2. Shifting a derailleur drivetrain
If your bicycle has a derailleur drivetrain, the gear-changing mechanism
will consist of:
x
a rear sprocket cluster, called a freewheel or freewheel cassette
x
a rear derailleur
x
usually a front derailleur
x
one or two shifters
x
one or two control cables
x
one, two or three front sprockets called chainrings
x
a drive chain
The number of possible gear combinations ("speeds") is the product of
multiplying the number of sprockets at the rear of the drivetrain by the
number of sprockets at the front (6 x 2 = 12, 6 x 3 = 18, 7 x 3 = 21
and so on).
a. Shifting Gears
There are many different types of shifter mechanisms, each preferred
for specific types of application because of its ergonomic, performance
and price characteristics. The designers of your bike have selected the
fig. 18C
up
shift
d o w n
s h i f t
down
shift
u p
s h i f t
fig. 18B
downshift
u p s h i f t
upshift
d o w n s h i f t
fig. 18A
downshift
u p s h i f t
upshift
d o w n s h i f t
fig. 18D
1
2
3
1
2
3
4
5
1
2
3
4
5
downshift
upshift
1
2
3
upshift
downshift
