OPERATING GEARS AND BRAKES
Derailleur Gears
Derailleur gears are the most common type of gear sys-
tems used on bicycles. They are the changing mechanism
used to move the drive chain up and down a series of cogs
or sprockets (the cluster or cassette stack) at the rear of
the bicycle and across the chainwheel at the front of the
bike (if fi tted). Multispeed bicycles today can range form
5-6 gears to as many as 30. Rear derailleurs are fi tted to all
multispeed bicycles while front derailleurs are only present
on those bicycles with the higher number of gears. Gears
enable the cyclist to select the most appropriate pedaling
resistance best suited for the riding conditions. The more
gears fi tted to the bicycle the greater choice available to
the rider.
Operating Principles
Although the number of gears present on multispeed bi-
cycles varies greatly, how the gears function remains the
same. The right shifter works the rear derailleur and the left
shifter works the front derailleur. If the pedals are station-
ary or rotating backwards, gears cannot be changed. They
can only be altered when pedaling forward. To achieve a
successful gear change, either moving up or down in gears,
the pedaling pressure must be relaxed. Failure to ease the
pressure when changing gears may result in bicycle damage
or could even cause the rider to lose control. If a rubbing
sound is detected after attempting to alter gears, adjust the
shifter until the sound ceases. Generally the lower gears are
for ascending hills and the higher gears are for descending.
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WARNING
:
Never attempt to force a pedal into a different
sized bicycle crank.
CRANK SET
Inspection and Maintenance
Every month the crank set should be checked to ensure that
it is properly adjusted.
For Three Piece Cranks:
• Check that the crank axle nuts are tight.
• Adjust the bottom bracket bearings as necessary.
• Remove the chain and test for crank movement on the
axle by attempting to move the cranks from side to side
with your hands. Only very slight movement in the bot-
tom bracket should be noted.
• Rotate the cranks. Adjust and oil if they do not spin
freely or a grinding noise is detected.
• Check the chainrings for any broken teeth, and clean off
any excess dirt and grease.
CAUTION:
Always ensure that your Three Piece cranks are
fi rmly secured before riding. Riding with loose
cranks is potentially hazardous to both the rider
and condition of the crank arms.
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