60
a
b
c
d
Multi-speed hubs (internal gear hubs)
Functioning and operation
The advantages of multi-speed hubs
(a+b)
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 influences of the
weather by a sealed chain box.
With multi-speed hubs normally the power transmission
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 (roller or drum brakes) that are actuated by a re-
verse 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 sys-
tems
“1” stands for the first, lowest gear. The gears are
shifted through one after the other, if possible without
turning the pedals, at least, however, at reduced ped-
al pressure. The highest number stands for the highest
gear.
NuVinci gear hubs
(c)
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 cy-
clist on the display
(d)
. 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 ca-
dence (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 compo-
nent manufacturers on this MERIDA CD-ROM.
Содержание BIG.NINE E-LITE 600
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