Terminology index

Question

It would be helpful to have a common place to list terminology, I'll start it off

Some Rules

• Make sure you only put one term per answer!
• Try to include an image if applicable
• Include sources that contain detailed information

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

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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.)

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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.

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Contents: (As of 03 Nov 2012)

Bearing
Bottom Bracket
BSO/Bike-Shaped-Object
Brifter
Cable Stretcher
Cadence
Chain Gauge
Chain Tool
Chain Tug/Chain Tensioner
Chainstay Length
Chamois
Clipless Pedals
Crank
Derailer Hanger/Derailleur Ranger
Disc Hub
Door Zone
Dunlop Valve
Fender/Mudguard/Mudflaps
Fixed-Gear
Flip-Flop Hub
Frame
Folding Bike
Gear Inches
Groupset
Handlebars
Headset
Hose Clamp aka Jubilee Clip
Hub Skewer
Hub
Internally-Geared Hub
Lawyer lips/lawyer tabs
LBS/Local Bike Shop
Luggage Carrier/Rack
Master Link
Mixte
Mountain Bike
Pannier
Power Meter
Presta Valve/Presta Tube
Quick-Release
Rim
Saddle
Saddlebag
Schrader Valve/ Schrader Tube
Skewer
Spoke
Stem
Tire Lever/Tire Iron
Track Pump/Floor Pump
Triathalon Bars/Triathlon Bars

Answer 1

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, in folded position

Answer 2

Hose Clamp

A.K.A. Jubilee Clip

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

Flashlight attached to handlebars with a series of hose clamps.

Jubilee Clip on Wikipedia

Answer 3

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.

• Sheldon Brown on cranks.

Answer 4

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:

   • Internally geared
   • Freewheel-compatible (hub has threads to which a freewheel can be attached)
   • Freehub (hub has splines to which a cassette can be attached)
   • Flip-flop
   • Track/fixed-gear

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.

Answer 5

Disc Hub

Disc hubs come in two varieties: 6-bolt ISO and Shimano's proprietary Centerlock spline. Converters exist to allow a Centerlock hub to accept a six-bolt disc rotor.

6-bolt ISO:

Shimano Centerlock: (Note, centerlock hubs ship with a rubber cover over the centerlock splines).

Answer 6

Chamois

The padding in a pair of bike shorts. Similarly, Chamois Cream is applied to the chamois to prevent chafing while riding.

Answer 7

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 suck as titanium or wood.

Aluminum mountain bicycle frame:

Parts of a bicycle frame:

(Image from wikipedia; credit and legalese)

Answer 8

Groupset

A groupset or gruppo (from the Italian for "group") generally refers to all of the components that make up a bicycle excluding the bicycle frame, forks, stem, wheels, tires, and rider contact points, such as the saddle and handlebars.

These parts typically include the following:

• gear levers / shifters and brake levers or integrated brake levers/shifters
• front and rear brakes (including calipers/pads or rotors/disks/pads)
• front and rear derailleurs
• bottom bracket
• crankset
• chain
• freewheel or cassette

With the following forming part of some groupsets:

• headset
• assorted cables and cable housings

Answer 9

Bottom Bracket

The bottom bracket is the bearing assembly that the cranks attach to.

The bottom bracket shell is the part of the frame holding the bottom bracket.

Generally, bottom brackets are made for a specific size of bottom bracket shell and a specific crank attachment.

Traditional bottom brackets are a piece that goes inside the shell and has the ends of a spindle/axle coming out on each end (which the crankset attaches to), or possibly the cranks somehow attach into it.

There are also external bottom brackets where the bearings are outside the bottom bracket shell, and the cranks have a spindle that runs through to the other side. Typically the bottom bracket in this case is a hollow cylinder with a bearing assembly permanently attached on one side and a way to attach the bearing assembly on the other (once inserted through the shell).

Most recently, there are various new-style ("press-fit", etc) bottom brackets, that are designed like an external bottom bracket, but rely on having a larger bottom bracket shell and fit inside the shell. They still have the axle/spindle as part of the cranks.

Also note that there are eccentric bottom brackets, which are really a bottom bracket that goes inside of an offset bottom bracket shell that fits inside the frame's bottom bracket shell. This allows the bottom bracket to be moved a bit, to tension the chain on a single-speed or fixed-gear bike.

• Sheldon Brown on bottom brackets

Answer 10

Master Link

AKA: Breakable Link, Powerlink™

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

More information at Sheldon Brown's site.

Answer 11

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.

Answer 12

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".

• http://www.sheldonbrown.com/gloss_m.html#mixte
• http://en.wikipedia.org/wiki/Step-through_frame#Mixte

Answer 13

Brifter

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

Reference:

• Wikipedia

Answer 14

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.

Reference:

• Sheldon Brown: Internal-Gear Hubs

Answer 15

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.

Answer 16

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.

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.

Answer 17

Power Meter

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

Reference: Wikipedia

Answer 18

Headset

The group of bearings and bearing cups that allows the steer tube to turn freely within the head tube. Headsets come in two basic varieties.

Threaded headsets are common on older bikes and inexpensive bikes. They are called "threaded" headsets because the top race is held on with a threaded race and locknut.

Threadless headsets are standard on modern mid-level and high-end bicycles. They are called "threadless" headsets because there are no threads on the race nor is there a lock ring. The headset is held together by pressure created by a bolt through the top cap which threads into a star nut inside the steer tube.

Images courtesy of Sheldon Brown.

Answer 19

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:

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.

Answer 20

Mountain Bike

Often abbreviated as MTB.

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

Some mountain bike come with a front suspension fork, some with front and rear suspension (known as full suspension). Mountain bikes with no suspension are also known as hardtails.

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