240:
spacing. An 8-speed cassette is wider at 41.5 mm than a second generation
Shimano 7. This results in functionally compatible shifters, but specific freehub bodies, or necessitating the use of a spacer with a 7-speed cassette on an 8-speed hub. 8- and 9-speed cassettes and freehub bodies have the same width (41.5 mm), yet the sprockets on the 9-speed are closer together; as a result the shifters are not compatible, but they use the same freehub bodies. This development continued with 10-speed cassettes, but branched out for 11-speed cassettes. With them, new freehub bodies emerged which were either wider (Shimano road 11-speed) or entirely different (SRAM XD, XDr, which differ in width and both provide the space for a 10-tooth cog). For 12-speed, Shimano introduced a new freehub body as well (Microspline).
119:, which can bend or even break. Multiple speed freewheels were common on quality high end bikes until the late 1980s. Suntour — Maeda Industries (Japan) introduced a compact 6 speed freewheel which reduced the spacing between the sprockets and was the same width as a standard 5 speed freewheel but required a narrower chain than the standard. The concept was copied by European freewheel manufacturers Regina (Italy) and Maillard (France). As the number of sprockets on a multiple freewheel increased, and became physically wider, the freehub design overcame the axle/bearing problem associated with threaded hubs and began to supersede the freewheel design. Today it is rare to find a freewheel on a new bicycle with more than 7 speeds. Some new
31:
87:
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engages a spline or set of notches on the outboard end of the freewheel. Removal often requires considerable effort due to the large torque that tightens the freewheel during pedaling, and some freewheels cannot be removed intact. Future removal of a freewheel is facilitated by grease on the freewheel threads before installation.
235:
both came up with independent standards, and SRAM later followed
Shimano's lead in respect to sprocket spacing and cassette width. The width of early Shimano 6- and 7-speed cassettes was 36 mm, and early 8-speed 40 mm wide. Shimano then changed again and standardised 8-11 speed cassettes on
239:
For
Shimano and SRAM the cassette spacing developed as follows. Early Shimano 7-speed cassettes are 36 mm wide, with sprocket spacing of 3.65 mm, but levers and rear derailleurs are not compatible with later Shimano 7-speed cassettes, which are 38 mm wide and have 3.2 mm sprocket
169:
The sprockets in a cassette are usually held together by three small bolts or rivets for ease of installation. These keep the sprockets and spacers in the correct order and position when they are removed from the freehub body. When the sprockets need to be replaced due to wear or the user wishes to
134:
Pedaling forces tighten a freewheel onto the hub, so no tool is required to install one. The ratcheting mechanism prevents the freewheel being loosened when the sprockets are turned counter-clockwise. A freewheel can be removed from the hub with one of the many specific freewheel removal tools that
106:
mechanism and mounts on a threaded hub. Threaded rear hubs were available in different thread patterns depending on the country of manufacture, French and
British threads being the most common. The British Cycle Engineers Institute (CEI) thread was adopted as the international standard and is now
114:
The major disadvantage of the multiple sprocket freewheel design is that the drive-side bearing is located inboard of the freewheel, and as sprockets were added over time, the bearing moved inward, farther from the drive-side axle support. This resulted in more flexing stress being placed on the
202:, to 5 used from the 1950s to the 1970s, up to the 8, 9, 10, 11, 12, and even 13 in the 2010s found on modern bikes. As more rear sprockets were added, the combination became wider, and the sprocket spacing narrower. One of the ways to make space for this was the axle length (measured as the
181:
The ratchet mechanism, known as the freehub body, is still replaceable on most hubs, but forms a structural part of the hub. Cassette systems have a major advantage in that the drive-side axle bearing can be out near the frame, rather than being back towards the centre of the axle behind the
218:
spacing was not shortened on threaded hubs, rather the axle length increased from 120 mm OLD (5-speed/compact-6) to 126 mm OLD (6-speed/compact-7) through to 130 mm OLD (threaded 7-speed) for a road bike. MTB rear spacing is normally 135 mm OLD. Another advantage of the
166:. Some cassette systems from the late 1980s and early 1990s use a threaded small sprocket to hold on the larger splined sprockets. Cassettes resemble freewheels when installed, but are clearly different when removed as they do not contain a freewheel's internal ratcheting mechanism.
247:" of the chain. This is caused by frictional abrasion of the load-bearing surfaces of the chain causing elongation. As such, the chain and sprockets of a 9-speed system require more frequent replacement than an 8-speed system. The narrowing of the hub flanges has created more
251:
in the wheel, which weakens the wheel if all other factors are the same, but improvements in the strength and reliability of spokes and rims has more than balanced this out, and wheel strength is generally higher despite the increased dish.
185:
Since their introduction in the late 1970s cassettes have been used on increasing numbers of bicycles, starting at the high-end and over time becoming available on less expensive bikes. Today the vast majority of bicycles with
223:
cassette hubs introduced from 1978 was that the rear hub flanges were wider apart than those of a threaded hub, so built a stronger wheel with less dish and without the problem of increased bearing stress or axle failure.
70:, of which cassettes are a newer development. Although cassettes and freewheels perform the same function and look almost the same when installed, they have important mechanical differences and are not interchangeable.
111:(BSC). It is a standardized right-hand 1-3/8″-24 TPI (M34.925×1.058 mm) thread onto which a standard freewheel is screwed. This allows different brands of freewheels to be mounted on different brands of hubs.
284:. The chain itself is specifically manufactured for ease of shifting, and to interface with a particular manufacturer's shift ramps; using a different type of chain may result in sub-optimal shifting.
243:
This progression has provided more fine adjustment of gear ratio, however the use of thinner metal parts has had the effect of shortening the life-span of the chain and sprockets due to so called "
236:
41.5 mm and second generation 7-speed to 38 mm. The widening of the sprocket carrier on the cassette hubs to 41.5 mm resulted in a decrease in the distance between the hub flanges.
231:
shifting, the width of a 5-speed or compact-6 freewheel was approximately 32 mm; the introduction of indexed shifting supposedly made standardized sprocket spacing necessary. Shimano and
268:
during shifting. They allow for shifting under greater load than was previously possible, and for smoother and cleaner shifting. The different systems are branded
214:
istance — OLD.) was increased, necessitating more dish on the rear wheel drive side with a threaded hub to centre the wheel in the frame. The hub
872:
174:
available, only the sprockets are replaced, not the ratchet mechanism. Cassettes also allow the use of sprockets with fewer teeth, as in
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Currently with a cassette hub you can run as small as an 8t sprocket. The smallest a freewheel hub can go is 13t.
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102:) consists of either a single sprocket or a set of sprockets mounted on a body which contains an internal
182:
freewheel. This greatly reduces the stress on the rear axle, making bent or broken axles extremely rare.
162:, which contains the ratcheting mechanism. The entire cassette is held on the hub by means of a threaded
881:
86:
994:
761:
120:
158:
that form the mechanical connection between the sprockets and the cassette compatible hub, called a
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902:
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952:
131: — and lower-end multi-geared bicycles continue to be manufactured and sold with freewheels.
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A freehub (above) for use with a cassette and a threaded hub (below) for use with a freewheel
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Cassettes are distinguished from freewheels in that a cassette has a series of straight
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Over time, the number of sprockets in a cogset has increased, from 3 or 4 before
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Shift ramps are complex tooth profiles, in the rear sprockets and front
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Park Tools webpage containing basic freewheel & freehub repair info
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or freewheel crank, a freewheel mechanism in the bottom bracket
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469:
27:
Set of sprockets attached to the rear wheel hub of a bicycle
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371:"Sheldon Brown: Traditional Thread-on Freewheels"
62:to the rider. Cassettes come in two varieties,
866:
551:
8:
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859:
851:
736:
558:
544:
536:
531:How to replace a cassette cluster (video)
396:"Sheldon Brown: Freewheel or Cassette?"
336:
50:that attaches to the hub on the rear
7:
438:. Dan's Competition. Archived from
264:, designed to pick up and drop the
719:Continuously variable transmission
46:or cluster is the set of multiple
25:
422:Cycleparts International Handbook
951:
504:from the original on 2009-12-31
402:from the original on 2008-08-18
377:from the original on 2017-09-20
352:from the original on 2017-10-06
471:. Van der Plas. Archived from
1:
596:Epicyclic (planetary) gearing
463:Frank J. Berto (1998-08-26).
194:Number and width of sprockets
82:A freewheel and freewheel hub
54:. A cogset works with a rear
227:Before the introduction of
1220:
949:
840:Spur gear corrected tooth
34:10-speed bicycle cassette
498:"Over-Locknut-Dimension"
436:"Wheels / Hub Tech Help"
256:Improvements in shifting
18:Freewheel (bicycle part)
190:use this newer design.
151:
109:British Standard Cycle
91:
83:
35:
420:Ron Kitching (1979).
146:
89:
81:
33:
995:Quick release skewer
762:Shaft-driven bicycle
465:"Sunset for Suntour"
150:cassette and freehub
58:to provide multiple
601:Sun and planet gear
304:Cycling terminology
280:, and OpenGlide by
123: — especially
830:Gear manufacturing
666:Geartooth profiles
346:"Bicycle Glossary"
152:
92:
84:
36:
1191:
1190:
848:
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793:
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616:Non-circular gear
581:Spur gear systems
98:(also known as a
16:(Redirected from
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344:Brown, Sheldon.
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276:, UltraDrive by
188:derailleur gears
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1219:
1218:
1214:
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1194:
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1183:Training wheels
1143:Luggage carrier
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714:Bicycle gearing
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611:Cycloidal drive
591:Rack and pinion
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320:Mountain biking
309:Front freewheel
294:Bicycle gearing
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933:Bottom bracket
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520:External links
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1204:Bicycle gears
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1128:Cyclocomputer
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882:Bicycle parts
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494:Sheldon Brown
489:
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475:on 2008-12-05
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442:on 2011-10-01
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129:utility bikes
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1077:Bowden cable
1036:
980:Spoke nipple
746:
699:Differential
694:Transmission
647:Spiral bevel
506:. Retrieved
488:
477:. Retrieved
473:the original
468:
458:
450:
444:. Retrieved
440:the original
430:
424:. Harrogate.
421:
415:
404:. Retrieved
390:
379:. Retrieved
365:
354:. Retrieved
339:
259:
242:
238:
226:
211:
207:
203:
200:World War II
197:
184:
180:
168:
153:
133:
121:single-speed
113:
99:
93:
67:
63:
43:
37:
1173:Skirt guard
1118:Bottle cage
1101:Peripherals
1082:Cable guide
1032:Master link
825:Chain drive
785:Wheel train
657:Herringbone
176:micro drive
172:gear ratios
60:gear ratios
1168:Reflectors
1163:Spoke card
1042:Derailleur
1005:Drivetrain
985:Valve stem
943:Suspension
898:Handlebars
820:Belt drive
805:Ball screw
752:Derailleur
586:Worm drive
508:2010-05-24
479:2008-09-25
446:2011-08-18
406:2008-08-18
381:2008-09-29
356:2010-05-24
331:References
278:Campagnolo
270:Hyperglide
262:chainrings
245:stretching
233:Campagnolo
104:ratcheting
74:Freewheels
64:freewheels
56:derailleur
1158:Saddlebag
1148:Mudguards
1133:Kickstand
1051:Gear case
1046:Hub gears
908:Head tube
835:Freewheel
815:Jackscrew
810:Leadscrew
687:Mechanics
178:systems.
139:Cassettes
107:known as
96:freewheel
68:cassettes
48:sprockets
1198:Category
1153:Panniers
1138:Lighting
1056:Sprocket
1018:Crankset
938:Fork end
923:Seatpost
798:See also
777:Horology
767:Sprocket
757:Hub gear
740:Bicycles
733:Examples
704:Coupling
673:Involute
502:Archived
400:Archived
375:Archived
350:Archived
325:Sprocket
315:Hub gear
288:See also
164:lockring
44:cassette
1123:Fairing
1092:Ferrule
1072:Shifter
1065:Cabling
990:Dustcap
913:Headset
678:Cycloid
652:Helical
574:Systems
299:Cycling
274:Shimano
229:indexed
221:Shimano
216:flanges
210:ocknut
170:change
160:freehub
156:splines
148:Shimano
40:bicycle
1178:Fender
1108:Basket
1037:Cogset
962:Wheels
928:Saddle
747:Cogset
724:Offset
625:Shapes
42:, the
1087:Brake
1023:Chain
1013:Pedal
975:Spoke
890:Frame
709:Train
642:Crown
637:Bevel
567:Gears
266:chain
100:block
52:wheel
38:On a
1113:Bell
1027:Belt
970:Tire
918:Fork
903:Stem
632:Spur
282:SRAM
249:dish
206:ver
127:and
117:axle
272:by
125:BMX
66:or
1200::
500:.
496:.
467:.
449:.
398:.
373:.
348:.
94:A
1044:/
1025:/
874:e
867:t
860:v
559:e
552:t
545:v
511:.
482:.
409:.
384:.
359:.
212:d
208:l
204:o
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
