Schwinn none - Manual (Page 84)

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2. Shifting a derailleur drivetrain
If your bicycle has a derailleur drivetrain, the gear-changing mechanism will consist of:
• a rear sprocket cluster, called a freewheel or freewheel cassette
• a rear derailleur
• usually a front derailleur
• one or two shifters
• one or two control cables
• one, two or three front sprockets called chainrings
• 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 shifter design which
they believe will give the best results on your bike.
The vocabulary of shifting can be pretty confusing. A downshift is a shift to a “slower” gear, one which is easier to
pedal. An upshift is a shift to a “faster”, harder to pedal gear. What’s confusing is that what’s happening at the front de-
railleur 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.