Derby cycle IMPULSE 2.0 - Derailleur Drivetrain Operation

Bicycle Owner’s Manual 19
d. Which gear should I be in?
The combination of largest rear and smallest ont
gears (g. 16) is for the steepest hills. The smallest rear
and largest ont combination is for the greatest speed. It
is not necessary to shi gears in sequence. Instead, nd
the “starting
gear” which
is right for
your level of
ability — a gear
which is hard
enough for quick
acceleration
but easy
enough to let
you start om
a stop without
wobbling — and
experiment with upshiing and downshiing to get a
feel for the dierent gear combinations. At rst, practice
shiing where there are no obstacles, hazards or other
trac, until you’ve built up your condence. Learn not
to use either the “smallest to smallest” or “largest to
largest” gear combinations because they may cause
unacceptable stress on the drive train. Learn to anticipate
the need to shi, and shi to a lower gear before the hill
gets too steep. If you have diculties with shiing, the
problem could be mechanical adjustment. See your dealer
for help.
WARNING: Never shi a derailleur onto the largest
or the smallest sprocket if the derailleur is not
shiing smoothly. The derailleur may be out of
adjustment and the chain could jam, causing you to lose
control and fall.
e. What if it won’t shi gears?
If moving the shi control one click repeatedly fails to
result in a smooth shi to the next gear chances are that
the mechanism is out of adjustment. Take the bike to your
dealer to have it adjusted.
2. How an internal gear hub drivetrain works
If your bicycle has an internal gear hub drivetrain, the
gear changing mechanism will consist of:
• a 3, 5, 7, 8, 11, 12, 14, 18 speed or possibly an
innitely variable internal gear hub
• one, or sometimes two shiers
• one or two control cables
• one ont sprocket called a chainring
• a drive chain
a. Shiing internal gear hub gears
Shiing with an internal gear hub drivetrain is simply a
a. Shiing Gears
There are several dierent types and styles of shiing
controls: levers, twist grips, triggers, combination shi/
brake controls and push-buttons. Ask your dealer to
explain the type of shiing controls that are on your bike,
and to show you how they work.
The vocabulary of shiing can be pretty consing. A
downshi is a shi to a “lower” or “slower” gear, one
which is easier to pedal. An upshi is a shi to a “higher”
or “faster”, harder to pedal gear. What’s consing is that
what’s happening at the ont derailleur is the opposite
of what’s happening at the rear derailleur (for details,
read the instructions on Shiing the Rear Derailleur
and Shiing the Front Derailleur below). For example,
you can select a gear which will make pedaling easier
on a hill (make a downshi) in one of two ways: shi
the chain down the gear “steps” to a smaller gear at the
ont, or up the gear “steps” to a larger gear at the rear.
So, at the rear gear cluster, what is called a downshi
looks like an upshi. The way to keep things straight is to
remember that shiing the chain in towards the centerline
of the bike is for accelerating and climbing and is called
a downshi. Moving the chain out or away om the
centerline of the bike is for speed and is called an upshi.
Whether upshiing or downshiing, the bicycle
derailleur system design requires that the drive chain is
moving forward and be under at least some tension. A
derailleur will shi only if you are pedaling forward.
CAUTION: Never move the shier while pedaling
backward, nor pedal backwards immediately aer
having moved the shier. This could jam the chain
and cause serious damage to the bicycle.
b. Shiing the Rear Derailleur
The rear derailleur is controlled by the right shier.
The nction of the rear derailleur is to move the
drive chain om one gear sprocket to another. The
smaller sprockets on the gear cluster produce higher
gear ratios. Pedaling in the higher gears requires greater
pedaling eort, 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 eort, but takes you a shorter distance with each
pedal crank revolution. Moving the chain om a smaller
sprocket of the gear cluster to a larger sprocket results in
a downshi. Moving the chain om a larger sprocket to
a smaller sprocket results in an upshi. In order for the
derailleur to move the chain om one sprocket to another,
the rider must be pedaling forward.
c. Shiing the Front Derailleur:
The ont derailleur, which is controlled by the le
shier, shis the chain between the larger and smaller
chainrings. Shiing the chain onto a smaller chainring
makes pedaling easier (a downshi). Shiing to a larger
chainring makes pedaling harder (an upshi).