Like this site? Help us to make it better.


A-Z of cycling jargon: find out what over 150 strange terms really mean

Bamboozled by all those technical terms? Help is at hand!

In the early 1980s comedian and keen cyclist Alexei Sayle gave an interview to Bicycle magazine in which he talked about the way bike shops guard their knowledge with language. "You ask for a hub," he said, "and they reply 'cross-threaded or off-flange?' and then they've got you!"

Cycling's technical jargon is one of the biggest hurdles when you're starting out, so here's a glossary of terms to help you out.

Anything we've missed? Let us know in the comments so we can make this listing as comprehensive as possible.

Cannondale CAADX 105 - rack mounts.jpg

Alloy: A mixture of one or more metals and other elements. Alloying changes the physical properties of the main metal. For example, the common 6061 aluminium alloy used for bike frames contains magnesium and silicon and has a yield strength roughly thirty times higher than pure aluminium.

Aluminium: Low-density metal used in various alloys for bike frames and components.

Aheadset: The original brand of threadless headset. Previously, headsets were adjusted by turning them on a thread on the steerer and holding them in place with a locknut. A threadless headset is held in place by the stem bolts after being preloaded by a bolt inside the steerer.

Anti-seize: Grease containing very fine metal particles, used to stop threaded parts from corroding together.

Bead seat diameter: Diameter of the tyre bead.

Bead seat: The part of the rim where the tyre bead sits. The diameter of the bead seat is the basis of rim and tyre size standards. For example the standard road bike wheel and tyre size, 700C, has a bead seat diameter of 622mm

Bead: see Tyre bead.

Token Tiramic bearings

Bearing: Any mechanism that reduces friction to allow parts to move easily against each other. Most common bicycle bearings use steel balls to allow parts to turn easily. Plain bearings, also known as bushings, have low-friction surfaces that slide against each other and are found in some components such as pedals and jockey wheels.

Belt drive: Bike transmission using a reinforced, toothed rubber belt instead of a chain.

Bimetallic corrosion: Aka galvanic corrosion; this is corrosion damage caused by a chemical reaction between two dissimilar metal surfaces and salt water. The most common example is aluminium seat posts corroding in place in steel frames because of the constant washing in salt water this area gets in a British winter.

Bolt circle diameter: The distance across an imaginary circle drawn through the centres of a crank's chainring bolts. Indicative of chainring compatibility, as long as the ring and cranks have the same number of bolts and the same bolt circle diameter, though Shimano's recent dalliance with asymmetrical crank arms made things complicated.

bottom bracket shell.jpg

Bottom bracket shell: The frame tube in which the bottom bracket mounts. May be threaded to accept a screw-in bottom bracket or smooth to take press-fit bearings.

Bottom bracket: The bearing on which the cranks turn, mounted in the bottom bracket shell at the lowest part of the frame.

Cable end cap: Metal cover used to prevent the end of a cable from fraying.

Cadence: Pedalling rate.

All-City Macho Man - Tektro Cantilevers Front

Cantilever brake: Brake that attaches to the frame tubes either side of the rim and has two separate pivots; used on hybrids and on older cyclocross and mountain bikes.

Carbon fibre: Composite material comprising very high strength carbon strands embedded in a resin matrix. Can have an extremely high strength-to-weight ratio and is therefore widely used for high-end bike frames and components.

Carcass: The body or casing of a bike tyre.

Cartridge bottom bracket: A crank bearing assembly in a single unit which cannot be serviced.

Casing: The body or carcass of a bike tyre.

Cassette: aka cluster, the collection of sprockets on the rear wheel.

Chain: An articulating assembly of links and pins used to transmit pedalling force from the chainrings to the sprockets

Bianchi Zurigo - chain stay cabling

Chain stays: The two thin frame tubes that run out from the bottom bracket to the rear wheel.

Chainguard: A protective cover around the chain.


Chainrings: The sprockets on the cranks, driven by the pedals that in turn act on the chain to turn the rear wheel.

Chainset: The cranks, chainrings and bottom bracket.

Chromoly: Very widely used class of steel alloys containing chromium and molybdenum to improve the steel's strength.

Shimano's SPD cleat is recessed into the sole of the shoe (CC BY-NC 2.0 Karlos:Flickr)

A Shimano SPD cleat, recessed into the sole of the shoe (CC BY-NC 2.0 Karlos:Flickr)

Cleat: Special stud in the sole of a shoe that engages with a clipless pedal.

Clincher: The most common type of bike tyre, featuring a wire bead that holds the tyre in place on the rim.

Look Keo 2 Max Blade 12 pedals

Clipless pedal: Pedal with a mechanism that engages a cleat in the sole of the shoe to provide a firm attachment for the rider's foot. So called because some pedals have metal or plastic cages — clips — to keep the foot in place on the pedal, usually with a strap around the foot.

Close-ratio gears: Gears with small gaps between one and the next, allowing the rider to maintain the same pedalling rate.

Cockpit: Term for the handlebar and stem, and sometimes the saddle and seatpost too, used by pretentious cycling writers who feel the strange need to give the impression they're flying a fighter plane rather than riding a bike.

Cog: A toothed wheel that engages with another toothed wheel. Not to be confused with a sprocket.

Cottered cranks: Usually made from steel, cottered cranks are held on to the bottom bracket axle by a shaped bolt — a cotter pin — that passes through the crank.

Cranks: The levers that connect the pedals and the chainrings. Cranks mount on the bottom bracket axle and are usually made from aluminium alloy or carbon fibre.

Mango Point R Tiagra - rear mech


Derailleur: A mechanism that changes gear by moving the chain between sprockets or chainrings.

Diamond frame: Frame with a high top tube; 'man's frame'.

TRP HyRd disc brake - rear

Disc brakes: Braking mechanism that acts on a specific braking surface attached to the wheel hub.

Double butted: Thicker at both ends than in the middle. In spokes, the spoke width changes, in frame tubes the thickness of the tube wall changes.

Down tube: The lower frame tube that runs from the headset to the bottom bracket.

Drop handlebar: The curved handlebar shape almost universally used on road-racing bikes and bikes that follow race bike styling such as touring bikes and gravel bikes.

Drive side: The right-hand side of the bike, where the chain and gears are.

Dropper post: A seatpost that includes a spring-loaded telescopic height-adjustment mechanism. Common on mountain bikes and sometimes seen on drop-handlebar gravel bikes.

Fat tyre bikes: Any bike with wide tyres; mountain bikes and budget, mountain bike-style bikes.

Ferrule: Cylindrical metal end-cap for a cable outer, with a hole for the inner to pass through

First gear: The lowest (easiest) gear.

Flange: The part of the hub shell into which the spokes fit.

Fork crown race: The part of the headset which fits on to the fork at the bottom of the steerer tube.


Fork: The two frame tubes that hold the front wheel, and by turning in the frame, allow the bike to be steered.

Frame size: The size of the frame, measured from the bottom bracket to the insertion of the seat post; determines what size of person the frame will fit.

Frame: The main structure of a bike. Determines the handling, supports the rider and mounts all the components.

Novatec R3 Disc wheelset - freehub

Freehub: Rear hub which includes the freewheel mechanism in its structure. The sprockets slide on to the freewheel and are held in place with a lockring. Has largely replaced the previous standard of a separate freewheel that screwed on to the rear hub.

Freewheel mechanism: Ratchet and pawl mechanism which allows the sprockets to spin freely in one direction and drive the hub in the other.

Fridge suck: The most powerful force in the cycling universe is the attraction between any small object dropped while working on a bike and the most inaccessible point under a nearby large object, such as the exact centre of the space under the fridge. This force increases with the level of groddiness of the crud under the fridge. It can be cancelled out for steel parts by the ownership of a magnetic pick-up tool.

Bianchi Zurigo - front mech

Front mech: The gear mechanism or derailleur which moves the chain across the chainrings.

Gear hanger: The part of the frame the rear mech is attached to. Usually part of the right hand side rear drop-out. On aluminium and carbon fibre frames, the gear hanger is removable so that a crash that damages it doesn’t write off the whole frame.

Gear range: The difference between highest and lowest gears.

Gear ratio: A measurement of gearing.

Hairsine ratio: The ratio between the weight saved by fitting a lightweight component and its cost. Named for Jon Hairsine, a rider prominent on the early British mountain bike racing scene. When asked how much he'd cut off a new carbon fibre handlebar to trim its size and weight, Jon replied: "About five quid!"

Look 765 - head tube badge.jpg

Head tube: The short frame tube at the front of the bike between the top tube and down tube. The headset sits in the head tube and allows the fork to turn.

Headset: The steering bearing assembly.

High gear: High gears on a bike come from the combination of a large chainring and small rear sprocket. That results in multiple turns of the rear wheel for each turn of the pedals, allowing high speeds.

Higher/lower gear range: Road bikes tend to have higher gears overall, hence they are referred to as having a high gear range, while the lower top and bottom gears of a mountain bike mean that it has a lower gear range.

hub gear.jpg

Hub gears: Gear system in which the mechanism is completely enclosed in the rear hub.

Hub shell: The outer part of the hub.

Hub: The central part of the wheel. The hub contains the bearings the wheels turn on, and the spokes attach to the hub flanges.

Hybrid: Bike with mountain bike gears and controls, and road bike size wheels.

Jockey wheels: The two small plastic wheels in the rear derailleur.

Knobblies: Deep-treaded tyres for riding off road.

Labyrinth seal: Seal made up of close- fitting steel collars which, filled with oil or grease, create a labyrinth which is difficult for dirt to penetrate.

Lacing: The initial stage of wheel building. Also, the way in which spokes are arranged so that they go under and over each other.


Locking compound: Liquid used to 'lock' threads together. Loctite is the most common and comes in various grades according to the size of threads being joined and how permanent the attachment needs to be. Also known as threadlock.

Lockring: Large nut used to hold a part in place. Most commonly, the special nut that holds a cassette in place.

Low gear: Low gears on a bike come from the combination of a small chainring and large rear sprocket. That results in fewer turns of the rear wheel for each turn of the pedals, allowing low speeds for climbing hills.

Low riders: Front pannier rack that holds the panniers low, next to the front wheel hub.

Lube: General term for any lubricant such as oil or grease.

Lycra shorts.jpg

Lycra: General term for stretch fabrics used for cycling and other sports clothing. The name comes from the elastic fibre that’s woven in with another yarn such as nylon or polyester usually in a mix that’s about 18% Lycra and 82% nylon. While the term has become generic, Lycra is a DuPont trademark; other manufacturers refer to it as spandex and elastane.

micro-adjusting seatpost.jpg

Micro-adjusting seat post: Post that provides fine adjustment of saddle angle.

Neoprene: Waterproof, insulating synthetic rubber originally used for wetsuits; common in winter cycling overshoes.

Non-drive side: The left-hand side of the bike, away from the chain and gears.

Nylok: Nuts with nylon inserts to prevent them from shaking loose.

Open frame: Frame with dropped top tube, often referred to as a woman's frame.

Shimano S3000R Overshoes.jpg

Overshoes: Shoe covers for winter cycling that help keep your feet drier and warmer.

Power meter: An electronic device that uses gauges to measure pedalling force and from that calculate the amount of power the rider is generating as she rides. Typically built into the cranks, pedals or bottom bracket axle, sometimes in the rear hub or chainrings.

Press-fit: Components that stay together because they have been forced, usually one inside the other, are said to be press-fit. The most common examples are bottom brackets and headsets.

presta valve.jpg

Presta: Thinner valve usually found on road bikes and higher-end mountain bikes.

quick release.jpeg

Quick release: A mechanism in the hub which allows the wheel to be easily removed and fitted without tools. A rod passes through a hollow axle and is tightened with a cam lever that clamps the drop-outs.

Quill stem: Handlebar stem that inserts into the fork steerer, rather than clamping around it. Usually used in conjunction with a steerer and headset that adjust by means of threads on the outside of the steerer.

Q-factor: The width of a pair of cranks, measured at the pedal eyes; the distance between the outer surfaces of the cranks at that point. Some riders, especially shorter people, find they are more comfortable with a smaller Q-factor. Also used to designate the distance between the outboard end of the pedal thread and the centre of the pedal mechanism.

Fork offset (1).jpg

Rake: The distance the front hub is offset from the steering axis (also called fork offset).

Cube Litening C68 Pro Blackline - rear mech

Rear mech: The gear mechanism or derailleur which moves the chain across the sprockets on the rear hub.

rim brake.jpg

Rim brake: Braking mechanism that acts on the side of the rim. Variants include side-pulls, cantilever brakes and V-brakes.

Rim well: The recess inside a rim where the spokes fit.

Rim: The outside of the wheel, on which the tyre is mounted.

Schrader: The type of valve usually found on car tyres. Used on some bikes, particularly cheaper mountain bikes, kids’ bikes and BMXes.

Screw-on freewheel: Separate freewheel mechanism that screws on to the hub body rather than being part of the hub structure.

Seal: Any part intended to protect a bearing or other fragile part from the ingress of water or dirt. Usually comprising a tight-fitting rubber ring, but see also labyrinth seal.

De Rosa King XS - seatpost

Seat post: The component that supports the saddle. Usually held into the frame by a clamp at the top of the seat tube, though some high-end frames have the seat post integrated into the frame as an extension of the seat tube.

Seat stays: The two thin frame tubes that run down from the seat-post to the rear wheel.

Seat tube: The vertical frame tube that runs from seat post to bottom bracket.

Shifters: The levers or other mechanism which activate the derailleurs.

Shifting: Changing gear.

Side-pull brakes: Brakes that attach to the frame above the tyre and are actuated by a cable at the side of the mechanism. Probably the most common brake design on road bikes, but increasingly supplanted by disc brakes on new bikes over around £1,000.

Sidewall: The sides of a tyre.

Sipes/siping: Grooves in the tread of a tyre intended to disperse water. Arguably unnecessary on bicycle tyres.

ritchey tom slick tread

Slick/semi slick tyres: Tyres with completely or partially smooth tread for road riding.

Spoke nipple: The special nut that holds the spoke into the rim.

Spokes: Shaped rods that connect the hub and rim of the wheel. The tension in the spokes gives the wheel its strength and ability to support loads far in excess of its own weight. Spokes are most commonly made from stainless steel, but may also be made from titanium, carbon fibre and aluminium.

Spoking pattern: The arrangement of the spokes within the wheel, usually referred to by the number of times a spoke is crossed by other spokes.

rear sprockets.jpg

Sprocket: A toothed wheel that meshes with a chain or toothed belt to transmit power from one part of the bike to another. Usually used to refer to those on the rear wheel; sprockets on the crank are called chainrings. Not to be confused with cogs, which mesh with each other.

Square taper: A design of bottom bracket and crank. The left and right cranks are separate from the bottom bracket axle. The ends of the axle are square in shape and tapered. Cranks mount via matching holes and are pulled into place with bolts. A tool called a crank puller is necessary to remove a square tape crank.

Squirrel: Arboreal rodent often encountered while riding. (Happy now, hawkinspeter?)

Stack and reach: The vertical and horizontal measurements from the centre of the bottom bracket to the top of the head tube. The most accurate indicator of how a bike will fit, but still only gradually coming into widespread use.

Steel: An alloy of iron and carbon, often with other elements added to tailor its properties. There are many varieties of steel, from simple carbon steel, composed of just iron and carbon, to alloy steels used for bike frames which usually have chromium, molybdenum and manganese alloying elements.

Steerer tube: The upper tube of the fork. Sits inside the head tube and is held in place by the headset bearings which allow it to turn. The handlebar stem attaches at the top of the steerer, clamping inside or around it depending on the design.

Norco Threshold C Rival 1 - stem

Stem: The component that joins the handlebar to the fork, aka handlebar stem. Old-style handlebar stems fitted inside the steerer; modern stems clamp around it.

Teflon: Very slippery polymer, also known as polytetrafluoroethylene (PTFE). Often used as very fine particles in bike lubes, it’s the same stuff used to coat non-stick pans.

Threads: The helical grooves in a screw or hole that a screw fits into.

Titanium: High strength to weight ratio metal used for bike frames and parts.

Top tube: The horizontal frame tube that runs from handlebar stem to seat post.

Truflo Digitrack track pump.jpg

Track pump: Floor-standing tyre pump.


Trail: The horizontal distance from where the front wheel touches the ground to where the steering axis intersects the ground, as shown in the above diagram. Trail affects handling; more trail makes a bike more stable at speed.

Transmission: The complete gear system; chainset, derailleurs, sprockets and chain.

Tread pattern: Any shaping, embossing or grooves in the tread of a tyre.

Tread: The section of a tyre that contacts and grips the road surface.

Tubeless: Tyres that have no inner tube but retain air because they fit very tightly on the rim, the rim is sealed by a special rim strip and the tyre either has an internal rubber coating or contains a liquid sealant that both coats the tyre and seals small punctures.

Zipp Tangente SLSpeed Tubular tyre

Tubular: Tyre that has the tyre casing sewn around the inner tube and is held on a special rim with glue.

Tyre bead: The wire round the inside of a tyre. As well as supporting the tyre shape, the bead hold the tyre in place on the rim. In most tyres the bead is made of steel; in lightweight tyres Kevlar is used to save weight, which also makes the tyre easy to fold for storage.

Tyre seat: The part of the rim where the tyre bead sits. A properly fitted tyre is therefore correctly 'seated'.

The Abus Granit X Plus is about as secure as a portable lock can be

U-lock/D-lock/Shackle lock: The highest-security bike lock design. An enlarged padlock with a locking mechanism in a hollow cylinder that engages the ends of a solid U-shaped bar.

Frog 52 - v-brake

V-brake: A rim brake with vertical arms, actuated by a cable that pulls across the top of the arms. Fits on the same mounts as a cantilever brake but doesn't require a

Wheel dish: The offset from the hub flanges necessary to centre the rim in the frame.

Woods valve: Tyre valve with a removable mechanism held in place by an external collar. The top thread is the same as that of a presta valve, so threaded pump adapters can be used, but it's usually too short for a press-fit or clamp-on pump head such as those usually found on track pumps. Also known as a Dunlop valve or English valve, though they're now very rare on anything but utility bikes intended for the Netherlands market.

John has been writing about bikes and cycling for over 30 years since discovering that people were mug enough to pay him for it rather than expecting him to do an honest day's work.

He was heavily involved in the mountain bike boom of the late 1980s as a racer, team manager and race promoter, and that led to writing for Mountain Biking UK magazine shortly after its inception. He got the gig by phoning up the editor and telling him the magazine was rubbish and he could do better. Rather than telling him to get lost, MBUK editor Tym Manley called John’s bluff and the rest is history.

Since then he has worked on MTB Pro magazine and was editor of Maximum Mountain Bike and Australian Mountain Bike magazines, before switching to the web in 2000 to work for Along with founder Tony Farrelly, John was on the launch team for and subsequently became editor in chief of Future Publishing’s group of cycling magazines and websites, including Cycling Plus, MBUK, What Mountain Bike and Procycling.

John has also written for Cyclist magazine, edited the BikeMagic website and was founding editor of before handing over to someone far more representative of the site's main audience.

He joined in 2013. He lives in Cambridge where the lack of hills is more than made up for by the headwinds.

Latest Comments