OHM bicycle, Руководство пользователя

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29
SHIFTING GEARS
OHM bicycles come equipped with lever style or twist-grip-style
shifters used to change your gears (see Fig 4.4a). Identify the
shifters on your bike before reading on.
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.
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 actually looks like an upshift. The way to keep things
straight in your head is to remember that shifting the chain in towards
the centre line of the bike is for accelerating and climbing and is
called downshifting. Moving the chain out or away from the bike’s
‘centerline’ is for speed and is called upshifting.
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.
CAUTION: Never move the shifter while pedaling backward,
nor pedal backwards after having moved the shifter. This could
jam the chain and cause serious damage to the bicycle.
SHIFTING THE REAR DERAILLEUR
The rear derailleur is controlled by the right lever or twist-grip-shift
on the handlebar.
The function of the rear derailleur is to move the drive chain from
one gear sprocket to another. The smaller sprockets on the gear
cluster produce higher gear ratios. Pedaling in the higher gears
requires greater pedaling effort, 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 effort,
but takes you a shorter distance with each pedal crank revolution.
Moving the chain from a smaller sprocket of the gear cluster to a
larger sprocket results in what we are calling a downshift. Moving
the chain to a larger sprocket results in an upshift. In order for the
derailleur to move the chain from one sprocket to another, the rider
must be pedaling forward.
Downshift
Upshift
Downshift
Upshift
Downshift
Upshift
Upshift
Downshift
Upshift
Downshift
1
2
3
1
2
3
4
5
Downshift
Upshift
Downshift
Upshift
Downshift
Upshift
Upshift
Downshift
Upshift
Downshift
1
2
3
1
2
3
4
5
Fig 4.4a