This review is hubs. Here is a detailed explanation
and history of hubs from around the world.
Since the turn of the century, internal-gear hubs, usually 3-speeds, have
offered a practical, reliable gear shifting option to the cyclist. With the
popularity of derailer gears taking off in the early 1970's bike boom,
internal geared hubs went out of style in most markets. This is unfortunate,
because many casual or utilitarian cyclists are best served by this type of
gearing.
Internal gear hubs are more reliable than derailer systems, and require
much less maintenance. Unlike derailers, they may be shifted even when the
bicycle is stopped, a valuable feature for the cyclist who rides in
stop-and-go urban traffic.
In the late 1990's, internal gears are undergoing something of a
renaissance, with the development of wide range 7-speed hubs. There are
currently 3 different brands of 7-speed hub available (although the Sturmey-Archer
Sprinter has very limited distribution at present.) This page shows the gear
ratios offered by each of the three. In addition, SRAM/Sachs offers a 12-speed
hub.
For example, if you use an 18 tooth sprocket on the
Shimano 7-speed hub, 7th gear would give you the equivalent of an 11.7
tooth sprocket.
While the charts below only list sprockets from 18 to 22 teeth, these are
not the only choices, and by selecting appropriate sized sprockets the overall
range of any of these hubs can be raised or lowered any desired amount. All of
the hubs shown here (except for the SRAM/Sachs 12 speed) take 3-splined
sprockets, and they are all interchangeable. These sprockets are available
from various sources from 13-22 teeth. It is also fairly easy to modify any
Shimano cassette sprocket that doesn't have a built-in spacer. These are
available from 14-34 teeth. Shimano cassette sprockets are the same diameter
as those used with internal gear hubs, but have 9 sprockets instead of 3. With
a suitable grinder, 6 of the splines need to be removed, and the corners of
the remaining three rounded off. A thin spacer washer may also be needed,
because the cassette sprockets are a bit thinner than the stock sprockets.
