General remarks How it works Lubrication Chainadjustment Anti-rotation Setting gear range with: 3

speeds 5 through 8 speeds 9 or more speeds HybridgearingInformation on specific brands and

modelsRohloff SRAM/Sachs ShimanoSturmey-Archer14-speed All, but alsosee links

below 3-speed 3-speed4-speed 4 and5-speed7-speed 7-speed9-speed 8-speed

8-speed12-speed 11-speed hybridGeneral remarks

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Since the first decade of the 20th century, internal-gear hubs, usually3-speeds, have offered a practical, reliable gear-shifting option to thecyclist With the popularity of derailer gears taking off in the early1970's bike boom, internal-gear hubs went out of style in most USmarkets This is unfortunate, because many casual or utilitariancyclists are best served by this type of gearing tn pascherInternal-gear hubs are more reliable than derailer systems, andrequire much less maintenance The step-up ratios of their top gearsmake oversize chainrings unnecessary on small-wheel foldingbicycles Unlike derailers, internal hubs can shift at a stop, very nicein stop-and-go urban traffic Internal-gear hubs tend to be heavierthan derailer systems, and are slightly less efficient in some gears The direct-drive middle gear can be more efficient than in a derailersystem, as there is no drag from derailer pulleys Most internal-gearhubs cannot have a quick-release axle If you are interested in oldbikes, or the history of this sort of gearing, refer to my page onEnglish Three Speeds How an internal-gear hub worksInternal-gearhubs work on the principle of "planetary gearing "The basic 3-speedhubs have a single "sun" gear solidly attached to the middle of theaxle 3 or 4 identical "planet" gears mesh with and revolve aroundthe "sun" gear The "planet" gears are surrounded by (and meshwith) a"gear ring" with its teeth on the inside (an inside-out gear) Asthe planet gears, attached to a part called a "planet cage", revolve,the gear ring revolves 4 times for every 3 times the planet cage goesaround (Some models have different ratios

)Low Gear has the sprocket driving the gear ring, while the planetcage drives the hub Thus, the wheel turns 3 times for every 4revolutions of the sprocket, lowering the gear by 25% Middle Gearhas the sprocket still driving the gear ring, but has the gear ring drivethe hub Thus, the drive is direct Although the internal gears arealways rotating when the sprocket is in motion, they don't have anyeffect on the drive in middle gear High Gear shifts the sprocket'sdrive to the planet cage, while the gear ring continues to drive thehub shell Thus, the hub turns around 4 times for every 3 sprocketrevolutions, giving a 33% gear increase There is a more detailedexplanation of this on the Sturmey-Archer Web site, from which Ilifted the image above Hubs with more than three speeds use two orthree planetary stages, and/or compound (stepped) planet gears withtwo or more sets of teeth side by side -- see John Allen's articledescribing these in more detail tn pas cherIn the late 1990's, internalgears underwent something of a renaissance, with the developmentof wide-range 7-speed hubs Progress has continued since Fourdifferent brands are currently available, with as many as 14 speeds Three-speeds and five-speeds are still currently in production, andthey offer an economical, practical alternative [Next three sectionsare by John Allen ]LubricationOlder internal-gear hubs have an oilfitting on the shell Oil lubrication generates less drag than greaseand washes wear particles, dirt and water out of the mechanism

Use machine oil, not a spray lube or other thin oil Unless a hub hassealed bearings, also use grease, to form a seal at the bearings andhelp keep the oil in The Rohloff Speedhub and the Shimano11-speed are oil-lubricated Other current internal-gear hubs aresupplied grease-lubricated As sold, they require periodic cleaningand replenishment of a special grease that does not make the pawlsstick Shimano sells a relubrication kit for grease-lubricated hubs Still, many hubs are inadequately lubricated as sold, and frequentfailures of grease-lubricated hubs due to water contamination havebeen reported in wet climates --see photos here Better lubricationsidesteps this problem It is best to add oil to the lubricant regimenwhen rebuilding a hub, so it gets a clean start and you also canregrease it This is desirable even with a new hub Follow theexample shown in the photos from Aaron's Bike Repair (near thebottom of the page, after you get past the horror-show photos ofrusted parts at the top) Use plenty of waterproof marine grease (asused in boat-trailer wheel bearings) for the bearing assemblies -- thiskeeps water out and oil in; use lightweight white lithium grease forthe gears, especially with modern wide-mouth hubs that hold oilpoorly; Phil Wood Tenacious Oil on the pawls and in the shell to sloparound and get to where the grease didn't reach An internal-gearhub with a hollow axle may be re-oiled by removing the pushrod orindicator spindle and squirting oil into the end of the axle The SRAMi-Motion 9-speed, disk brake model, can be oiled through a diskbrake rotor hole Plug all the fixies bikes holes with machine screwsbetween oilings

On a hub which doesn't allow one of these tricks, you could install aSturmey-Archer oil cap Tools: #3 (or 5 5 mm) drill and a 1/4 inch 28TPI tap A simpler but less convenient approach is to unscrew theleft bearing cone and squirt oil in past the left end of the axle Oil canaccumulate on the hub shell, and can become a bit messy, but, bigdeal On the other hand, if used to excess, oil can run down thespokes onto the rim, soften the brake shoe rubber and make a rimbrake squeal and grab This is hazardous in a front wheel, but theinternal-gear hub is in the rear wheel Cleaning the oil andbrake-shoe rubber deposits off the rim restores brake function Also,it is best to store your bicycle in an unheated (but dry) area Whenyou 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 storeyour bike in a heated area, be especially careful about keeping thehub oiled Old Sturmey-Archer coaster-brake 3-speeds have an oilfitting, but other hubs with a coaster brake require a specialhigh-temperature grease for the brake shoes Some hubs use adifferent grease for the rest of the mechanism, so the pawls don'tstick A coaster brake in an internal-gear hub is, all in all, a poor ideabecause of the wear particles it generates, and because you can'tuse oil lubrication Oil lubrication may cause problems with a drumbrake, by seeping out past the bearing and contaminating the brakeshoes

Phil Wood Tenacious Oil stays in place better than most other oils Unlike with derailleur bicycle, if you must store or transport the bikehorizontally, lay it on its right side This will prevent oil from leakinginto the drum Place something under the rear wheel to catch thedrip, especially if you have just oiled the hub Shimano roller brakesare sometimes referred to as drum brakes, but are actually similar tocoaster brakes They use steel brake shoes inside a steel drum andrequire periodic lubrication with high temperature grease Adjustingthe chainInternal-gear hubs typically use a single sprocket and singlechainwheel The chain is held in place by moving the hub's axleforward or backward in the dropout slots until the chain is just barelyslack Details of how to do this are in another article on this site Abicycle with vertical dropouts must have an eccentric bottom bracket,or a chain tensioner must be installed As the chain wears, itlengthens, and it is more likely to fall off It must be readjustedperiodically Technique for chain adjustment is described in thearticle on fixed-gear bicycles Anti-rotationThe axle is part of the geartrain of an internal-gear hub You can check this out for yourself

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

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 areaction arm instead of anti-rotation washers On a bicycle with rearsuspension, 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 therear end of the bicycle, reducing "pogo sticking" in gears below 1:1;the opposite in gears above 1:1 Pogo-sticking reduces pedalingefficiency, to a degree which depends on the design of thesuspension click here

fixies bikes