1. General remarks How it works Lubrication Chain
adjustment Anti-rotation Setting gear range with: 3
speeds 5 through 8 speeds 9 or more speeds Hybrid
gearingInformation on specific brands and
modelsRohloff SRAM/Sachs Shimano
Sturmey-Archer14-speed All, but alsosee links
below 3-speed 3-speed4-speed 4 and
5-speed7-speed 7-speed9-speed 8-speed
8-speed12-speed 11-speed hybridGeneral remarks
fixies bikes

2. Since the first decade of the 20th 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-gear hubs went out of style in most US
markets This is unfortunate, because many casual or utilitarian
cyclists are best served by this type of gearing tn pas
cherInternal-gear hubs are more reliable than derailer systems, and
require much less maintenance The step-up ratios of their top gears
make oversize chainrings unnecessary on small-wheel folding
bicycles Unlike derailers, internal hubs can shift at a stop, very nice
in stop-and-go urban traffic Internal-gear hubs tend to be heavier
than derailer systems, and are slightly less efficient in some gears
The direct-drive middle gear can be more efficient than in a derailer
system, as there is no drag from derailer pulleys Most internal-gear
hubs cannot have a quick-release axle If you are interested in old
bikes, or the history of this sort of gearing, refer to my page on
English Three Speeds How an internal-gear hub worksInternal-gear
hubs work on the principle of "planetary gearing "The basic 3-speed
hubs have a single "sun" gear solidly attached to the middle of the
axle 3 or 4 identical "planet" gears mesh with and revolve around
the "sun" gear The "planet" gears are surrounded by (and mesh
with) a"gear ring" with its teeth on the inside (an inside-out gear) As
the planet gears, attached to a part called a "planet cage", revolve,
the gear ring revolves 4 times for every 3 times the planet cage goes
around (Some models have different ratios

4. )Low Gear has the sprocket driving the gear ring, while the planet
cage drives the hub Thus, the wheel turns 3 times for every 4
revolutions of the sprocket, lowering the gear by 25% Middle Gear
has the sprocket still driving the gear ring, but has the gear ring drive
the hub Thus, the drive is direct Although the internal gears are
always rotating when the sprocket is in motion, they don't have any
effect on the drive in middle gear High Gear shifts the sprocket's
drive to the planet cage, while the gear ring continues to drive the
hub shell Thus, the hub turns around 4 times for every 3 sprocket
revolutions, giving a 33% gear increase There is a more detailed
explanation of this on the Sturmey-Archer Web site, from which I
lifted the image above Hubs with more than three speeds use two or
three planetary stages, and/or compound (stepped) planet gears with
two or more sets of teeth side by side -- see John Allen's article
describing these in more detail tn pas cherIn the late 1990's, internal
gears underwent something of a renaissance, with the development
of wide-range 7-speed hubs Progress has continued since Four
different brands are currently available, with as many as 14 speeds
Three-speeds and five-speeds are still currently in production, and
they offer an economical, practical alternative [Next three sections
are by John Allen ]LubricationOlder internal-gear hubs have an oil
fitting on the shell Oil lubrication generates less drag than grease
and washes wear particles, dirt and water out of the mechanism

5. Use machine oil, not a spray lube or other thin oil Unless a hub has
sealed bearings, also use grease, to form a seal at the bearings and
help keep the oil in The Rohloff Speedhub and the Shimano
11-speed are oil-lubricated Other current internal-gear hubs are
supplied grease-lubricated As sold, they require periodic cleaning
and replenishment of a special grease that does not make the pawls
stick Shimano sells a relubrication kit for grease-lubricated hubs
Still, many hubs are inadequately lubricated as sold, and frequent
failures of grease-lubricated hubs due to water contamination have
been reported in wet climates --see photos here Better lubrication
sidesteps this problem It is best to add oil to the lubricant regimen
when rebuilding a hub, so it gets a clean start and you also can
regrease it This is desirable even with a new hub Follow the
example shown in the photos from Aaron's Bike Repair (near the
bottom of the page, after you get past the horror-show photos of
rusted parts at the top) Use plenty of waterproof marine grease (as
used in boat-trailer wheel bearings) for the bearing assemblies -- this
keeps water out and oil in; use lightweight white lithium grease for
the gears, especially with modern wide-mouth hubs that hold oil
poorly; Phil Wood Tenacious Oil on the pawls and in the shell to slop
around and get to where the grease didn't reach An internal-gear
hub with a hollow axle may be re-oiled by removing the pushrod or
indicator spindle and squirting oil into the end of the axle The SRAM
i-Motion 9-speed, disk brake model, can be oiled through a disk
brake rotor hole Plug all the fixies bikes holes with machine screws
between oilings

7. On a hub which doesn't allow one of these tricks, you could install a
Sturmey-Archer oil cap Tools: #3 (or 5 5 mm) drill and a 1/4 inch 28
TPI tap A simpler but less convenient approach is to unscrew the
left bearing cone and squirt oil in past the left end of the axle Oil can
accumulate on the hub shell, and can become a bit messy, but, big
deal On the other hand, if used to excess, oil can run down the
spokes onto the rim, soften the brake shoe rubber and make a rim
brake squeal and grab This is hazardous in a front wheel, but the
internal-gear hub is in the rear wheel Cleaning the oil and
brake-shoe rubber deposits off the rim restores brake function Also,
it is best to store your bicycle in an unheated (but dry) area When
you take it out from a heated area in cool, moist -- or wet -- weather,
the air inside the hub contracts, pulling in moisture If you must store
your bike in a heated area, be especially careful about keeping the
hub oiled Old Sturmey-Archer coaster-brake 3-speeds have an oil
fitting, but other hubs with a coaster brake require a special
high-temperature grease for the brake shoes Some hubs use a
different grease for the rest of the mechanism, so the pawls don't
stick A coaster brake in an internal-gear hub is, all in all, a poor idea
because of the wear particles it generates, and because you can't
use oil lubrication Oil lubrication may cause problems with a drum
brake, by seeping out past the bearing and contaminating the brake
shoes

9. Phil Wood Tenacious Oil stays in place better than most other oils
Unlike with derailleur bicycle, if you must store or transport the bike
horizontally, lay it on its right side This will prevent oil from leaking
into the drum Place something under the rear wheel to catch the
drip, especially if you have just oiled the hub Shimano roller brakes
are sometimes referred to as drum brakes, but are actually similar to
coaster brakes They use steel brake shoes inside a steel drum and
require periodic lubrication with high temperature grease Adjusting
the chainInternal-gear hubs typically use a single sprocket and single
chainwheel The chain is held in place by moving the hub's axle
forward or backward in the dropout slots until the chain is just barely
slack Details of how to do this are in another article on this site A
bicycle with vertical dropouts must have an eccentric bottom bracket,
or a chain tensioner must be installed As the chain wears, it
lengthens, and it is more likely to fall off It must be readjusted
periodically Technique for chain adjustment is described in the
article on fixed-gear bicycles Anti-rotationThe axle is part of the gear
train of an internal-gear hub You can check this out for yourself

10. If you hold the hub shell or rim when the hub is not installed on the
bicycle and turn the sprocket, the axle also turns -- backwards if the
hub's drive ratio is lower than 1:1, forwards if higher Special
anti-rotation washers keep the axle from turning when the wheel is
installed on the bicycle These washers engage flat surfaces on the
axle, and have tabs that fit into the dropout slots Different washers
fit different models of hubs and dropout slot widths Many newer
hubs attach the shifter cable to a pulley that rotates around the hub's
axle, between the right dropout and the sprocket Depending on
whether a bicycle has horizontal, vertical or reversed (track)
dropouts, different washers are needed so the shift cable can
approach from the front of the bicycle Follow the instructions for
each hub Anti-rotation washers for Shimano Nexus internal-gear
hubsA hub brake of any kind also must resist rotation Brakes on
internal-gear hubs use a reaction arm for this purpose, separate from

11. the anti-rotation washer(s) for the gearing You must install them too
The Rohloff hub has such a wide gear range that some models use a
reaction arm instead of anti-rotation washers On a bicycle with rear
suspension, the suspension's pivot is usually ahead of the rear hub
Because it tries to rotate the hub's axle, an internal-gear hub lifts the
rear end of the bicycle, reducing "pogo sticking" in gears below 1:1;
the opposite in gears above 1:1 Pogo-sticking reduces pedaling
efficiency, to a degree which depends on the design of the
suspension click here

12. fixies bikes