18
Shifting Gears
Your multi-speed bicycle will have a derailleur drive train, an internal gear hub drive train or in some special cases a combination of the two.
How a Derailleur Drive Train Works
If your bicycle has a derailleur drive train, the gear changing mechanism will have:
•
A rear cassette or freewheel sprocket cluster
•
A rear derailleur
•
Usually a front derailleur
•
One of two shifters
•
One, two or three front sprockets called chain rings
•
A chain drive
Shifting Gears
There are several different types and styles of shifting controls, levers, twist grips, triggers, combination shift/brake controls and push buttons. Ask your
dealer to explain the type of shifting controls that are on your bike, and to show you how they work.
A downshift is a shift to a “lower” or “slower” gear, one that is easier to pedal. An upshift is a shift to a “higher” or “faster” harder to pedal gear. To
select a gear that will make pedalling easier on a hill, make a downshift in one or two ways; shift the chain down (the gear “steps” to a smaller gear at
the front) or shift the chain up (the gear “steps” up to a larger gear at the rear). So at the rear gear cluster, what is called a downshift actually moves the
chain up to a larger gear. The way to keep things straight is to remember that shifting the chain in towards the centre line of the bike is for accelerating
and climbing and is called a downshift. Moving the chain our or away from the centre line 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 pedalling forward.
Shifting the Rear Derailleur
The right shifter controls the rear derailleur.
The function of the rear derailleur is to move the drive chain from one gear sprocket to another. The smaller sprockets on the rear wheel gear cluster
produce higher gear ratios. Pedalling in the higher gears requires greater pedalling effort, but takes you a greater distance with each revolution of the
pedal cranks. Using them requires less pedalling effort, but takes you a shorter distance with each pedal crank revolution. There are two screws or limit
screws on the rear derailleur body that limit the travel of the rear derailleur. Tightening the rear derailleur high gear adjustment screw keeps the chain
folding bike manual.indd 18
20/06/2011 11:00:20
