Glossary of old-bike terms

The part of the frame where the cranks turn: the bottom bracket shell, and the axle and bearings that run through it.

Checked against Sheldon Brown's glossary · See also Bottom bracket standards

A small fitting fixed permanently to the frame, such as a cable stop, gear lever boss, pump peg or bottle cage mount. On steel frames they're brazed on, which gives them the name.

Checked against Sheldon Brown's glossary

A row of small dents worn into a headset race by the bearing balls. It causes 'indexed steering', where the bars stick in the straight-ahead position.

Checked against Sheldon Brown: servicing headsets · See also Headset standards and servicing

Frame tubing with thicker walls at the ends than in the middle, usually with the same outside diameter all the way along. It puts the strength where the stresses are greatest and saves weight in between.

Checked against Sheldon Brown's glossary · See also Reynolds 531, 501 and high-tensile steel

A rim brake in which one assembly moves both brake blocks, fixed by a single bolt through the fork crown or the brake bridge between the seat stays. Side-pull and centre-pull brakes are both callipers.

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A rim brake with two separate arms, one each side of the rim, each pivoting on its own boss on the frame or fork. The arms are usually joined by a straddle cable running above the tyre.

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A calliper brake where the main cable comes down the middle of the bike and pulls a straddle cable joining the two arms. Sheldon Brown says they were popular from the late 1960s to the early 1980s.

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How straight the chain runs between the chainring and the rear sprocket. Ideally they line up exactly; on a bike with derailleur gears the line is only perfect in some gears.

Checked against Sheldon Brown's glossary · See also Chainline figures

A shiny plating on steel or brass parts that gives some protection against rust. Chromium is also alloyed into steel to make it tougher, as in chrome-moly.

Checked against Sheldon Brown's glossary · See also Cleaning chrome

Steel alloyed with small amounts of chromium and molybdenum, used for most good-quality steel frames and forks. Reynolds 501 is a chrome-moly tube set.

Checked against Sheldon Brown's glossary · See also Reynolds 531, 501 and high-tensile steel

The normal kind of tyre, with a separate inner tube. Its edges, called beads, are hoops of steel or Kevlar that hold it on the rim.

Checked against Sheldon Brown's glossary · See also Getting the tyre size right

An older way of fixing the cranks to the bottom bracket axle, using cotters: wedge-shaped pins with a thread at one end for a nut.

Checked against Sheldon Brown's glossary · See also Cotter pins on our Tools page

The later kind of three-piece crankset. The axle usually has square tapered ends that fit matching tapered holes in the cranks, held tight by a bolt or nut. There are two square tapers, JIS and ISO; mixing them puts the crank about 4.5mm out of place.

Checked against Sheldon Brown's glossary · See also JIS and ISO square tapers

The traditional loose-ball bearing, with the balls running between a cup and a cone. In a threaded bottom bracket the cones are part of the axle and the cups screw into the frame; the left-hand cup is the one you adjust.

Checked against Sheldon Brown's glossary · See also Bottom bracket tools

The mechanism that moves the chain from one sprocket or chainring to another. A rear derailleur has a cage with two pulleys: the jockey pulley and the tension pulley.

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A fork end is the slotted plate that holds a wheel axle, at the bottom of each fork blade and where the seat stays meet the chain stays. A drop-out is the kind that lets the rear wheel come out without lifting the chain off first; track and BMX bikes have fork ends that open to the rear.

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The British name for a bicycle generator. Sheldon Brown points out that 'generator' is technically the better word, because bicycle generators produce alternating current.

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Sturmey-Archer's hub generator, built into hubs such as the AG and FG.

Checked against Sheldon Brown: Sturmey-Archer cribsheet · See also Dynohub on our Parts page

The tyre and rim sizing system, now an ISO standard, that gives the tyre width and the rim's bead seat diameter in millimetres, as in 37-590. The second number is the one that has to match your rim.

Checked against Sheldon Brown's glossary · See also Getting the tyre size right

A rear hub with the sprocket fixed to it and no freewheel. The pedals turn whenever the wheel turns, so you can't coast.

Checked against Sheldon Brown's glossary · See also Fixed-gear lockring tools

A rear hub with the freewheel built into the hub instead of the sprocket cluster, so the sprockets slide on as a cassette. Freehub is a Shimano trade mark.

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The ratchet that lets the bike roll on when you stop pedalling. On older derailleur bikes it's part of the sprocket cluster, and each make needs its own remover.

Checked against Sheldon Brown's glossary · See also Freewheel removers

The maker's badge on the front of the head tube. Velobase collects them to help identify a frame's maker, country and age.

Checked against Velobase · See also How old is my bike?

The bearings that join the fork to the frame and let it turn. A headset has four races: the crown race, the lower and upper head races, and the adjustable race.

Checked against Sheldon Brown's glossary · See also Headset standards and servicing

Plain steel tubing used for everyday and cheaper frames; Sheldon Brown calls it the ordinary tubing for cheap frames. Raleigh's catalogues name grades such as 20-30 and 18-23.

Checked against Sheldon Brown's glossary · See also Reynolds 531, 501 and high-tensile steel

A brake built into the wheel hub instead of working on the rim. Back-pedal hub brakes are called coaster brakes; hand-operated ones include drum brakes. They work as well in the wet as in the dry.

Checked against Sheldon Brown's glossary · See also Sturmey-Archer hub brakes

Gears built inside the rear hub, using planetary gearing, such as the Sturmey-Archer AW 3-speed.

Checked against Sheldon Brown's glossary · See also Servicing a Sturmey-Archer 3-speed hub

Gear levers with a click stop for each gear. Older friction levers have no click stops.

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A socket joining two or more frame tubes. On traditional steel frames the tubes are brazed or silver-soldered into the lugs.

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The vertical part of a traditional handlebar stem. A traditional pedal used with toe clips and straps is also called a quill pedal.

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The traditional utility bicycle: usually 28 × 1½in (37-635) wheels, rod brakes, a chain case and relaxed angles, and most often black.

Checked against Sheldon Brown's glossary · See also Getting the tyre size right

Brakes worked by steel rods instead of cables. Most use a stirrup that pulls the blocks against the inside of the rim, on Westwood or Raleigh pattern rims.

Checked against Sheldon Brown's glossary

The British name for a seat post, especially the plain tube type with a separate saddle clamp.

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A calliper brake where the inner cable pulls one arm and the outer cable pushes the other, usually with both on the same side.

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The British hub gear maker that grew up with Raleigh: its first three-speed patents date from 1902, when a new department was set up at the Raleigh works. Its hub codes, such as AW, are stamped on the hub shell along with the date.

Checked against Our Parts page and its sources · See also Sturmey-Archer on our Parts page

Cages on the pedals, used with straps to hold your feet. The straps do the holding; the clips keep them open so you can slip your foot in.

Checked against Sheldon Brown's glossary

The British name for the decals on a frame, such as the maker's name, the model and the tubing label.

Checked against Our guide to protecting transfers · See also Stripping a bike without damaging the transfers

A true wheel's rim is perfectly round and runs straight. Truing means adjusting the spokes to get it there; a wheel out of round gives a bumpy ride.

Checked against Sheldon Brown's glossary · See also Wheel truing and rim checks

A racing tyre with no beads: the casing is sewn closed around the inner tube and glued onto a special rim. Tubulars use Presta valves.

Checked against Sheldon Brown's glossary