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This question and its answers list the names of bike parts and cycling concepts.

Some Rules

  • Make sure you only put one term per answer!
  • Try to include an image if applicable
  • Include sources that contain detailed information
  • Add a link to the index in this question using edit.

Also, I made this a community wiki, so that anyone will be able to edit it, and to stop rep-hoarding


There's a handy reference at the Park Tool Co. website, a bike repair map; it's a diagram of a bike with all the parts labeled, and is very handy! At the moment, the diagram is up at parktool.com/blog/repair-help. (They've changed the URL in the past, so this link may break.)

A road bike has the following parts (source):

enter image description here

A mountain bike has the following parts (source): enter image description here


Edit: This page is meant to identify what things or concepts are (as per this thread in meta). If you want to recommend an accessory or a specific product you've found handy, please use the accessories page.


Contents: (As of 03 May 2014)

Axle
Axle Nuts
BCD (Bolt Circle Diameter)
Bearing
Bonk/Bonking
Bottle Cage / Bottle Holder
Bottom Bracket
Brazed Frame
Brifter
BSO/Bike-Shaped-Object
Cable Pull
Cable Stretcher
Cadence
Chain Gauge
Chain Guard/Cover
Chain Tool
Chain Tug/Chain Tensioner
Chainstay Length
Chainsuck
Chamois
Clipless Pedals
Coaster Brake (foot brake / pedal brake)
Crank
Derailer Hanger/Derailleur Ranger
Disc Hub
Door Zone
Dropout
Dunlop Valve
Fender/Mudguard/Mudflaps
Fixed-Gear
Flip-Flop Hub
Folding Bike
Frame
Gear Inches
Groupset
Handlebars
Headset
Hose Clamp aka Jubilee Clip
Hub
Hub Skewer
Internally-Geared Hub
Lawyer lips/lawyer tabs
LBS/Local Bike Shop
Luggage Carrier/Rack
Lugged Frame
Master Link
Mixte
Mountain Bike
Pannier
Play
Power Meter
Presta Valve/Presta Tube
Pump Peg
Quick-Release
REI (Recreational Equipment Inc)
Rim
Rim Tape
Saddle
Saddlebag
Schrader Valve/ Schrader Tube
Single-speed
Skewer
Spider
Spoke
Stem
Through/Thru Axle
Tire Clearance
Tire Lever/Tire Iron
Tire Saver
Track Pump/Floor Pump
Triathalon Bars/Triathlon Bars
Welded Frame

  • 6
    one term per answer would be beneficial – dotjoe Aug 26 '10 at 13:51
  • 1
    Should we add an "Anything not mentioned here" link? (With a link to sheldonbrown.com/glossary.html, of course.) – jensgram Aug 26 '10 at 15:22
  • 1
    Is there a way to link to a specific answer, so that in future questions you can use one of these terms and link to it for reference? – Kevin Aug 26 '10 at 16:13
  • 2
    Kevin: Under the bulk of the answer, there is a 'Link' hyperlink, which will link to the answer (its right above comment) – Dan McClain Aug 26 '10 at 17:12
  • 7
    @MarkIngram: useful things that aren't atually questions are what community wikis are for. – freiheit Sep 12 '10 at 17:47

72 Answers 72

9

Luggage Carrier

(a.k.a. Rack)

A luggage carrier, or rack, is a frame attached to a bicycle to provide space for a pannier or other back to be attached. They are frequently mounted over the rear wheel and are typically bolted to the bicycle and not easily removed.

Heavy-duty rear rack on a touring bike: enter image description here

Reference:

9

Hub Skewer

A replaceable part of a hub that attaches the hub/wheel assembly to the fork or frame. Some are equipped with a quick-release mechanism that allow removing the wheel without tools, facilitating changing a tire, putting a bike in the back seat of a car, etc. Unfortunately, the trade-off for easy wheel removal is that it's easier for thieves to remove a quick-release wheel.

enter image description here

9

Chainstay Length

A critical measurement used to help determine a proper chain length for any given bicycle. The chainstay length is measured from the center of the front chainring (centered on the bottom bracket spindle) to the center of the rear cog (centered on the rear axle).

Touring bicycles typically have longer chainstays to allow for more heel clearance when riding with panniers, but this comes at the cost of increased flex due to longer tubes. Bicycles designed for sprinting and for the track typically have extremely short chainstays.

Chainstay Length + Front Center Distance = Wheelbase

Chainstay Length

Relevant: Chain length calculator

9

Brifter

A combined brake and shift lever. Also referred to as integrated shifters.

brifter

Reference:

9

Frame

The frame is the skeleton of a bicycle. It's the part that all other parts are attached to. (Some parts, like the front wheel, are attached to other parts that are in turn attached to the frame.) The fork is sometimes considered a part of the frame, even though it's attached to the frame mechanically.

Frames are commonly made of steel, aluminum, carbon fiber, and sometimes more exotic materials such as titanium, wood, or bamboo.

Aluminum mountain bicycle frame:

100_7864

Parts of a bicycle frame:

enter image description here

(Image from wikipedia; credit and legalese)

8

Saddlebag

(a.k.a. seat bag, wedge bag, etc.) Small bag designed to be attached to the underside of a bicycle saddle, usually large enough to hold tools to change a flat tire.

The name "saddlebag" is often mistakenly applied to panniers which resemble saddlebags used on motorcycles or horse saddles.

  • also known as a wedge-bag/pack – mgb Oct 22 '10 at 3:52
8

Hub

One of the central parts of a conventional bicycle wheel. A hub is essentially a flanged metal tube (somewhat similar in shape to a spool of thread). The hub links the rim, axle, and (in the case of rear hubs) drivetrain of a bicycle:

  1. Rim

    Holes are drilled in the flanges of the hub so that the spokes may be threaded through the hub, which holds the "heads" of the spokes. The spoke nipples in the rim hold the other ends of the spokes. This is how the hub is connected to the rim.

  2. Axle

    The hub also has a lateral hole through which the axle is inserted. When the wheel is moving, the axle does not rotate, but the hub, spokes, and rim do. The axle does not contact the hub directly; the two components have a set of cups/cones, bearings, and locknuts holding them together, similar to headsets and head tubes. This is how the hub (and thus the rest of the wheel) is connected to (but rotates freely around) the axle.

  3. Drivetrain

    In order to provide a means by which the chain can rotate the wheel, rear hubs can have at least one cog attached. (Front hubs do not have any drivetrain components.) There several different types of rear hubs which accept various drivetrain systems:

Furthermore, some hubs (front and rear) are designed to accept disc brake pads, while some other hubs (rear only) have drum or coaster brake systems built-in.

  • What is the actual name of the cylinder on which cassette goes? Wikipedia states "splined shaft", here you use term just "splines". – greenoldman Mar 26 at 18:31
8

Folding Bike

AKA Folder

A bike that's designed to fold down to a small package without disassembly. They usually have smaller wheels, and are designed to be taken on trains and buses. Many transit organizations that don't allow bikes during peak hours will allow folding bikes during these busy times. They also reduce storage space requirements, often useful in city apartments.

There are also bikes that do not fold, but are designed to be taken apart easily, with frame latches, quick-release latches, or hybrid folding/unlatching systems.

Folding bike, ready to ride

Folding bike, ready to ride

Folding bike, in folded position

Folding bike, in folded position

8

Internally-Geared Hub

A setup where, instead of the cogs and derailleur mechanisms are on the outside of the wheel, they're sealed in the rear wheel's hub. As the gears are sealed away from water and road salt, internally-Geared hubs require much less in the way of cleaning than traditional drive-trains. These hubs are popular with commuters or other utility cyclists that will be ride in the snow and rain. They are also popular on folding bikes, as they are suited for bikes taken on crowded trains. When coupled with a single front chainring, IGH drivetrains permit the installation of a full chain guard, which most external gear systems don't allow.

Internal hubs are slightly heavier than comparable external drive-trains.

Hub

Reference:

8

Lawyer Lips/ Lawyer Tabs

Bicycle forks with quick-release wheel mechanisms are often equipped with these. The intent is to make it less likely that the wheel will accidentally release if the quick-release lever is used improperly.

lawyer lips (thanks to sk606 for the image)

In practice, they make it difficult to use the quick-release without unscrewing the skewer, making the quick-release harder to use.

These are named what the are because of the rumor that these were added to bikes for liability reasons.

For bikes with disk brakes they are properly promoted to the role of retaining ridges. Under braking loads the wheel tries to twist out of the dropouts and the ridges serve to prevent that.

7

Crank

The part of the bicycle that the pedals screw into. The cranks themselves are, in turn, attached to the bottom bracket. The front chainring (or chainrings) attach to the crank.

Crank arms

6

Hose Clamp

A.K.A. Jubilee Clip

A ratcheting clamp often used to attach items to a bicycle fork or handlebars.

Flashlight attached to flat handlebars with a series of hose clamps.

Flashlight attached to handlebars with a series of hose clamps.

Jubilee Clip on Wikipedia

  • 1
    I see how the clamp goes around the torch, but how does it attach to the bars? Is there a second clamp, or does it twist around? – Hugo Jun 20 '11 at 8:59
  • 1
    There's a second clamp. – Neil Fein Jun 20 '11 at 14:14
  • 6
    Hose clamps can cut into paint an even metal if they're tight enough. You can stick a strip of old inner tube under the clamp to prevent this (and to provide better grip). – naught101 May 12 '12 at 3:03
6

Rim

The circular, U-shaped (in cross-section) part of a bicycle wheel that the tire and spokes are is attached to. Wheel-building is the process of attaching a hub to a rim with spokes; the name has connotations of smaller runs of wheels that are not machine-built, and are of presumably higher quality.

6

Spoke

The spokes connect the hub of a wheel to its rim. Spoke count is the number of spokes in a wheel, and a higher spoke count usually means a stronger wheel that can handle more weight and abuse.

Spoke tension (the force with which the spokes are tightened) can be adjusted individually. This is part of the process of truing a wheel, ensuring that tension is equally distributed in the wheel and that the rim is true, or straight. This is particularly important with bikes that have tight tolerances, but wheels that are trued are a benefit to any bike.

6

Tyre Saver

Small loop of wire attached so that it rubs continuously on the tyre as it rotates. This brushes off debris and reduces the number of punctures. These were popular mainly in the 1970's and 1980's, with the advent of lightweight puncture-resistant tyres they have almost disappeared.

tyre saver

  • Good work Mσᶎ. I think we also called them stone pickers or tire pickers, but my recent research only found stone picking machines to remove stones from farmland. – andy256 Jun 10 '14 at 3:41
6

Master link

Also known as:

  • Quick link
  • Breakable link
  • PowerLink™ (made by SRAM)
  • MissingLink (made by KMC)

A link inserted onto a chain so that the chain can be both assembled and "broken" (disassembled) without a chain tool. A set of pliers or a flathead screwdriver is usually sufficient to disassemble a chain with a master link.

Master link pliers are available to open a master link. Note that not all designs of master link are sold as suitable for re-use.

More information at Sheldon Brown's site.

enter image description here

Image from Wikipedia

6

Chamois

The padding in a pair of bike shorts. Sometimes chamois cream is applied to the chamois to prevent chafing while riding.

  • 5
    And chamois cream is better known as "butt butter". – Daniel R Hicks Jul 31 '11 at 18:24
5

Mixte

A mixte is a step-through (low top tube or "ladies") frame with 3 sets of stays instead of the usual two. The middle set of stays usually runs all the way to the head tube replacing the top tube, but on some mixte frames, the top tube is still a normal single tube. The traditional mixte has those axle-to-head stays straight, but there are also designs where they're bent to give an even lower standover height. They still retain the usual chain stays and seat stays. This design keeps the frame strong and doesn't require a longer seat post.

I believe the word itself comes from French and means "mixed" as in "mix of women's and men's styles" or maybe even "unisex".

5

Cage/Bottle Cage/Bottle Holder

This is a mechanism to hold water bottles on a bike frame. They can be made of steel, aluminum or carbon. Most attach to the frame via preinstalled threaded holes, although on older frames an attachment that wraps around the entire tube was needed as an adapter. A couple examples of cages are shown:

Carbon Fibre Aluminum

For time trials and triathlons, there are also cage adapters that attach to the seat and provide mounting points for extra water bottle cages and spare tubes/inflators, and a few new mounts place a water bottle between the extension of an aerobar set.

Behind the seat Between the extensions

5

Mountain Bike

Often abbreviated as MTB.

A bike with sturdier wheels (usually 26" or 29") and wider tires - around 2" wide - meant for riding off-road.

Mountain bikes commonly come with only front suspension (hard tail), front and rear suspension (full suspension) or no suspension (rigid; also may be referred to as a hard tail). A rare configuration is the soft tail where only rear suspension is present.

Thicker frame tubing and flat handlebars are common features of mountain bikes.

5

Spider

The part that connects the cranks to the chain rings. Typically spiders have 5 legs, but 3, 4, and six legs are also common.

Image from trekstorecolumbus.com

5

Welded Frame

A frame made by melting the tubes it is built from at the joins, typically with a similar metal added as filler. Mass produced aluminium and steel frames are almost all built this way as with modern machines it is very fast and cheap.

welded frame joints

5

Bonk

Expression used by cyclists to describe exercise induced low blood sugar levels; being a feeling of light-headedness and weakness in all limbs.

Similar to The Wall in running. Has fallen out of usage in recent years due to alternative meanings.

The cure is to stop riding and eat something sweet. Water and electrolyte won't help. You also need to rest for a while.

Also known as Crashing, Blowing Up, or Running out of Steam/Gas/Fuel, or Empty Tank.

Its not a pleasant feeling, and should be avoided by eating regularly on long rides.

5

Brazed Frame

see also lugged frame and welded frame

A method of joining frame parts together by melting brass into the joins between frame tubes. Frames can be fillet brazed or use lugs, which are extra, normally cast steel, parts that the frame tubes slot into before brazing. Lugs make building a strong frame easier, provided you have exactly the right lug for the situation. Fillet brazing offers more freedom, but also more skill is required to produce a strong joint.

Shown is part of a fillet brazed frame, with the grey steel contrasting with the copper-coloured bronze

fillet brazed frame

This contrasts with welding, where the parent metal is melted and the same or a very similar metal is added as filler.

4

Chain guard/Chain cover

It's a frame, usually made of plastic or metal, that covers the entire length of the chain or only the upper part, mainly for protecting the rider from the dirt and lubricant on the chain, but can also protect the chain itself.

http://commons.wikimedia.org/wiki/File:Bike_chain_guard_full.JPG

http://upload.wikimedia.org/wikipedia/commons/thumb/6/69/Bike_chain_guard_part.JPG/320px-Bike_chain_guard_part.JPG

4

Power Meter

A power meter is a device on your bicycle to measure the power output of the rider.

See also What is a power meter and why do I need one?

Image of power meter

Reference: Wikipedia

4

Lugged Frame

also lugs

A method of frame-building where at least the major joints consist of frame tubes inserted into castings (the lugs). Occasionally lugs are hand-made by bending and filing rather than casting. Lugged frames are normally brazed, but can also be soldered (with lead or silver rather than brass) and occasionally glued (the Windcheetah trike used glued aluminium, for example). Historically this was very common, and many classic steel frames were built this way. Today with better welding technology it's rare, especially in mass produced bikes.

classic Italian lugged frame

4

Pump Peg

A pump peg is a small protrusion on a bike frame which is intended to facilitate the mounting of a "frame pump". Depending on the style of the frame, the peg may be positioned to allow the pump to fit on the underside of the top tube (of a standard diamond frame) or on the trailing side of the down tube. The peg is designed to mate with a corresponding hole in the end of the pump.

Some schemes have a peg at each end, while others reply on the other end of the pump being wedged into the V formed by the top tube and seat tube.

enter image description here

enter image description here

4

Thru Axles / Through Axles

These axles are more like bolts for your wheels. Historically bicycles have used dropouts for both wheels, but the advent of MTB and disc brakes has shown a requirement for a system that cannot drop the wheel under braking, and adds stiffness.

A Through Axle looks more like a hollow pipe, compared with a conventional QR as per: from http://cdn.mos.bikeradar.imdserve.com/images/news/2014/02/14/1392416431992-ecxclyd8c6n5-700-80.jpg

A Through Axle has no dropouts - as this image shows there is a solid line of white metal from the fork all the way around From http://fcdn.mtbr.com/attachments/beginners-corner/789715d1365723144-need-help-new-bike-assembly-thru-axle-axle-pic.jpg

Contrast with Quick Release

The purported advantages are:

  • Increased stiffness when turning
  • Shock Load is shared between both fork legs more evenly
  • Less rotational torsion on the fork leg with the brake caliper attached.
  • Thicker axles are harder to break - a 15mm axle has more strength than a 9mm QR.
4

Single-speed

This means a bike that has exactly one rear cog, and cannot change gear. Very similar to a fixed-speed bike (fixie) except a single-speed has a freewheel mechanism to allow coasting, or riding/gliding along without pedaling.

Compare with Fixed-Gear.

protected by Gary.Ray Sep 5 '14 at 13:36

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