As time went on, the Bicycle Glossary has grown, and many of the pages became inconveniently large.I have split the larger pages into smaller ones, but I realize that there may be external links pointing to the older pages. For this reason, I have maintained copies of the older pages at the same location.
This is one of the older pages, and the newer pages that were derived from it are liable to be more complete and up to date, so please follow the links below to the current version. Sorry for any inconvenience.
If one of my own pages had a link that took you to this page, it would be helpful if you would send me an email with the URL of the page that had the bad link, so I can update it.
Sheldon Brown
Some standard spacings:
91 mm Low-end front hubs. 96 mm Older front hubs, especially French. 100 mm Modern front hubs. 110 mm Rear older track, coaster brake and other single-speed hubs. Also, front hubs for Downhill bikes with 20 mm axles. 114 mm Rear 3-4-speed . 120 mm Rear 5-speed, Ultra 6, newer track hubs. 126 mm Rear 6- and 7-speed (road). 130 mm Rear 7-speed (MTB) and 8- 9- and 10-speed (road). 135 mm Rear 7- 8- and 9-speed (MTB) 140 mm Rear tandem. 145 mm Rear tandem (newer models.) 150 mm Retro-Choppers, some Downhill and Freeride models. 160 mm Rear tandem (new Santana proposed standard.)
Some newer cassettes also use a spider to connect the sprockets to the freehub body. This is done primarily to save weight.
Some frame tubing has internal ribs to reinforce the tube, these are sometimes also referred to as splines.
A conventional spoke has a swaged head, like the head of a nail, to keep it from pulling throgh the flange of the hub. Immediately after the head the spoke takes a right-angle bend, also known as the "elbow" of the spoke. (See also straight spokes) The outer end of the spoke is threaded, and a special nut called a nipple fits through the rim and screws onto the spoke threads.
Traditionally, most bicycles have had 36 spokes in each wheel. British bicycles, for years, used to use 40 spokes in the rear, and 32 in the front. This was a better system for the consumer, because the strength of the wheels was in better proportion to the stresses on them. It makes things easier for the manufacturers, however, to use the same number of spokes front and rear. This results in a front wheel that is needlessly heavy, and/or a rear wheel that is not as strong as it should be.
In the last few years, 32 spoke wheels have become increasingly common. Manufacturers tout this as an advantage, because it saves a very small amount of weight (they don't mention that it is also cheaper!) For most cyclists, the reduced strength and repairability of 32 spoke rear wheels is a greater detriment than the very tiny improvement in performance they offer.
(courtesy of Damon Rinard)
Brand Model Material Diameter Length
(MM)Count Weight
(Grams)Litespeed titanium 2.0 267 32 122 DT Revolution stainless 2.0/1.55 266 32 134 Wheelsmith 1.8DB stainless 1.8/1.55 266 32 135 FiberFlight Æro plastic 266 32 136 Wheelsmith 1.8DB stainless 1.8/1.55 267 32 146 DT 1.8DB stainless 1.8/1.6 266 32 156 DT 1.8 stainless 1.8 266 32 179 Wheelsmith 2.0DB stainless 2.0/1.7 273 28 159 Wheelsmith 2.0DB stainless 2.0/1.7 298 32 182 DT 2.0DB stainless 2.0/1.8 266 32 193 DT 1.8 stainless 1.8 291 16 97 Wheelsmith 2.0 stainless 2.0 264 16 107 Wheelsmith 2.0 stainless 2.0 266 16 109 Wheelsmith 2.0 stainless 2.0 267 32 218 DT 2.0 stainless 2.0 266 32 221 DT 2.0 stainless 2.0 289 16 120
(courtesy of Damon Rinard)
Brand Gauge/
DiameterMaterial Weight Comments Hi-E 15/1.8 aluminum 0.235 requires special socket wrench Wheelsmith 14/2.0 aluminum 0.344 DT 15/1.8 brass 0.850 old style disc shaped DT 14/2.0 brass 1.000 new style trumpet shape Wheelsmith 14/2.0 brass 1.063 DT 15/1.8 brass 1.100 new style trumpet shape DT 14/2.0 brass 1.140 old style disc shaped Fiber Flight 14/2.0 plastic 7g/36 (claimed weight)
There are also "novelty" or fad lacing patterns, including the "crow's foot" and "snowflake" designs. These patterns are eye catching, but have no practical advantage.
Spoke patterns are discussed at some length in my wheelbuilding article.
The front sprockets are also commonly called chainwheels or chainrings. The term "sprocket" is perfectly correct to refer to either front or rear, but use of "sprocket" to refer specifically to a front one is mainly confined to BMX usage.
The rear sprockets individually are also commonly called cogs or gears; as a group they are referred to as a block or cluster or freewheel.
The "sprung" weight is the weight of the part of the vehicle and its payload which is held up by the springs. In the case of a suspension-equipped bicycle, the sprung weight would include most of the frame, and the rider. In the case of a rigid-frame bicycle, the "sprung" weight would consist of the rider's trunk and head, while the rider is off the saddle, carrying his or her weight on bent knees/elbows.
The "un-sprung" weight is the weight of the wheels, and the parts of the suspension that move up and down with the wheels as they track over bumps.
When a bump lifts a wheel up, the spring compresses. After the wheel passes over the bump, the spring pushes the wheel back down into contact with the ground. In the case of a vehicle with a low sprung/un-sprung weight ratio, such as one with heavy wheels and a light rider, the wheel will not move back into contact with the road surface as fast as it would with a higher sprung/un-sprung weight ratio.
If the wheel is heavy, the spring will not be able to push it back into contact with the ground as fast as the same spring could push a lighter wheel.
If the rider is light, the spring force will also be light, so it will not be able to push the wheel back down as fast as the stronger spring that would be used with a heavier rider could push the same wheel.
If the rider is light, but the spring is strong, the rider will not get enough benefit from the suspension, and the strong spring will lift the rider as well as the wheel.
The primary bicycle application for stainless steel is for spokes. Virtually all modern high-quality spoked wheels are built from stainless steel spokes.
Stainless steel is also used for high quality control cables.
Although steel is used for most high-quality bicycle frames, the use of steel instead of aluminum for many parts is often the result of penny pinching. Nobody should have to ride a modern bicycle with steel rims, brakes or handlebars. The only reason steel is now used for these parts is to scrimp on costs.
This was not always the case. As recently as the 1960's, steel was favored for many of these parts, particularly by the British. Indeed, for many years, Raleigh's slogan was "The All-Steel Bicycle". Steel parts of this era were often high in quality.
A conventional stem consists of a shaft (which telescopes into the steerer) and an extension of some sort which runs forward from the shaft to the clamp that holds the handlebar. Types of stems:
On fixed-gear bicycles that only have a single brake, some riders install a stoker lever on the other side of the handlebar for symmetry.
The modern bent design surplanted "straight pull" spokes in the 1890's. Since no bicycle technology ever disappears entirely, straight spokes get re-invented from time to time, but have not met with commercial success in the last hundred years.
A similar effect occurs with other materials, including those used to build bicycle frames. Good design avoids placing stress risers in heavily loaded areas of the frame.
Jane Thomas has kindly posted excerpts from the 1956 Sturmey-Archer service manual
In addition to adding to the comfort of the rider, suspension systems improve traction on bumpy surfaces, by keeping the tires in more nearly constant contact with the surface. (See sprung/unsprung weight) They also help protect the wheels from damage, by allowing them to spring out of the way when they hit something forcefully.
It is published by Sutherland Publications, Box 9061, Berkeley, California 94709.
Synch chains connect equal-sized chainwheels, so the mechanical advantage is 1:1. This is true for all size synch chainwheels, as long as they are both the same size. Smaller synch chainwheels, however, put a greater stress on the synch chain, the frame, and the bottom bracket bearings, so it is a mistake to make them too small in an attempt to save weight. Typical sizes are in the range of 38 teeth and up.
See also my article on adjusting tandem synch chains.
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