53
e
f
g
Multi-speed hubs (internal gear hubs)
Functioning and operation
The advantages of multi-speed hubs
(d+e)
are their
enclosed design. Unlike derailleur gears the gear
drive is within the hub body, only the primary ratio
from the chainwheel to the sprocket being outside.
What is more, all the gears can be shifted through
with one gear shifter.
Provided that it is serviced regularly, the drive chain
has a comparatively longer service life. And this
applies even more if it is protected from the influ-
ences of the weather by a sealed chain box.
With multi-speed hubs normally the power trans-
mission and the gear ratio adjustment is guaranteed
via one or several planetary gears, depending on
the number of gears. To shift gears the pedal force
should be reduced shortly.
In contrast to derailleur gears, multi-speed hubs
cannot only be combined with manually actuated
brakes (rim, drum, roller or disc brakes), but also with
back-pedal brakes
(f)
(roller or drum brakes) that
are actuated by a reverse rotation of the pedals. The
most effective braking is achieved with the pedals in
the horizontal position.
In the case of multi-speed hubs and gearbox shift
systems “1” stands for the first, lowest gear. The
gears are shifted through one after the other, if pos-
sible without turning the pedals, at least, however, at
reduced pedal pressure. The highest number stands
for the highest gear.
NuVinci N360 gear hubs
(g)
are designed to allow
stepless shifting by means of a twist grip within their
range of gear ratio. With the NuVinci hub the force
transmission is ensured by balls instead of toothed
wheels. Make it a rule to shift only while pedaling at
reduced force.
With NuVinci the actual gear ratio is indicated to the
cyclist on the display. If the cyclist climbs uphill, the
gear ratio is low; on level ground the gear ratio is high.
The H-Sync gear system integrates the NuVinci
Harmony
®
gear hubs into the Intuvia system of its
Bosch drive. With H-Sync you can predefine your
preferred cadence (between 30 and 80 turns per
minute). The drive readjusts automatically – both
uphill as well as downhill. This allows you to always
maintain your preset cadence.
For more information see the instructions of the
component manufacturers on this CENTURION
CD-ROM.
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