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

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 2

Derailleur hanger

The part of the bicycle frame that the rear derailleur screws into. It can be integral part of the frame or, for safety, a separate replaceable piece.

Answer 3

Cadence

Cadence is the number of revolutions of the crank per minute.

Cyclists typically have a preferred cadence at which they feel most comfortable, and on bicycles with many gears it is possible to stick to a favourite cadence at a wide range of speeds. Recreational and utility cyclists typically cycle around 60–80 rpm; racing cyclists around 80–120 rpm and sprinters up to 170 rpm for short bursts. The professional racing cyclist and Tour de France champion Lance Armstrong is known for his technique of keeping up high cadences of around 110 rpm for hours on end to improve efficiency¹

¹ http://en.wikipedia.org/wiki/Cadence_(cycling)

If you are getting pain in your knees, it could be that your cadence is too low. A cadence between 80-100 will probably reduce knee pains, as stated in bicycling.com or more detailed at Cycling Performance Tips web site.

Answer 4

Cable Stretcher

A.K.A. "Fourth Hand" brake tool

The cable stretcher is used to stretch brake cables when installing brakes or new cable. It can also be used to tighten zip ties.

Answer 5

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.

Answer 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.

Answer 7

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 8

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 9

Triathlon bars or Aerobars

Aerodynamic bike handlebars are for racing bicycles and particularly time trial bicycles.

Included are narrow, bolt-on extensions that draw the body forward into a tucked position, pursuit bars that spread the arms of the rider but drops the torso into a slightly lower position, and integrated units that combine elements of both designs.

Triathlon bars are commonly used in triathlons and time trial events on road and track. However, they are illegal in most mass start road races or any other event where drafting is permitted because, while aerodynamically advantageous, they tend to draw the hands away from brakes, make the rider slightly more unstable on the bike, and can be dangerous in the event of an accident. Further, they are not useful in sprints or shorter climbs where power is of greater importance than aerodynamics.

There is a distinct set of aerobars that are utilised in draft legal triathlons on regular road frames. As draft legal (ITU sanctioned) triathlon races require road frames that are UCI legal, a stubby pair of arms has been developed for this style of racing.

Sources:

• http://en.wikipedia.org/wiki/Bicycle_handlebar#Triathlon_or_aero

• http://www.beginnertriathlete.com/cms/article-detail.asp?articleid=1414

Answer 10

Stem

Attaches the handlebars to the bike, or, more precisely, to the steer tube (when using a threadless headset) or fork (when using a threaded headset). Many different sizes and angles of stems are available, so that the rider can place the handlebars where they will be the most comfortable during riding. There are also adjustable stems made, so the rider may change bar positions without removing the handlebars.

More information at Sheldon Brown's site

Adjustable stem on a touring bike, attached to the headset with risers, with the handlebars removed

Answer 11

Quick-release

The term "quick-release" - often abbreviated as "QR" - usually refers to a quick-release axle, a device that allows the removal of a bicycle wheel without tools.

Quick-release axle

"Quick-release" also refers to several other types of quick-release mechanisms that are popular on folding bicycles, such as collapsible seatposts and folding frames.

Answer 12

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 13

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 14

BSO

Bicycle Shaped Object: A derogatory term for a very cheaply produced bike aleged to have very low quality components which can break when attempting to adjust them:

For instance the BSO pictured is being sold in the UK by ASDA (owned by Walmart) for £75. These bikes tend to be mass produced and sold in flat pack boxes which must be assembled.

It is more advisable to search for a cheap second-hand bike in a similar price range on eBay than to go for one of these.

Answer 15

Chain Tug

AKA: Chain Tensioner

A device for use on bikes with horizontal dropouts, and normally with a fixed or single speed or hub gear. The chain tug(s) allow the chain tension and rear wheel alignment to be adjusted, and to stop the rear wheel from pulling forward while pedaling.

Some chain tugs are available with derailleur hangers to allow horizontal droput bikes to run derailleur gearing systems.

More information about chain tugs is available in this answer.

Bottom Bracket mounted Chain Tensioners:
Typically seen on downhill styled mountain bikes.

Answer 16

Power Meter

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

Reference: Wikipedia

Answer 17

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 18

Brifter

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

Reference:

• Wikipedia

Answer 19

Pannier

A pannier, pronounced pan-yer /ˈpanyər, ˈpanēər/ (US) or pan-i-er /ˈpanɪə/ (UK) ^[1], is a bag designed to be mounted on the side of a bicycle rack. Bags can be made of nylon, canvas, or waterproof materials such as PVC. Rear is most common, but smaller panniers intended for a front rack are also available.

Often erroneously called a saddlebag because a pannier on a motorcycle or horse is attached to the saddle.

Answer 20

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 21

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 22

Fixed-Gear

AKA: Fixie

A fixed-gear bike has the rear gear locked to the hub, which fixes the pedals rotation to the rear wheels rotation. In other words, you can't coast: The pedals are always in motion as long as the bike is. Track bikes are commonly fixed-gear.

The sprocket is screwed directly onto a fixed hub. When the rear wheel turns, the pedals turn in the same direction. This allows a cyclist to stop without using a brake, by resisting the rotation of the cranks, and also to ride in reverse.

More information: http://en.wikipedia.org/wiki/Fixed_gear

Answer 23

LBS

LBS is the acronym commonly used for Local Bike Shop. The term is usually used when comparing small, privately owned shops with large chains, big box stores, and internet shops.

http://www.flickr.com/photos/johnprolly/5728618798/

Answer 24

Chamois

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

Answer 25

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

Relevant: Chain length calculator

Answer 26

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 27

Chain Tool

Used to 'break' a chain by punching out one of the link rivets. Needed to shorten a new chain to the correct length or to replace a broken link.

A chain link is placed in the open slot and the handle turned to force a pin into the rivet pushing it out of the other side.

The rivet isn't normally reusable - the chain is remade with a special link that joins the chain without a tool--usually called a master link.

Answer 28

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 29

Flip-Flop Hub

Most often seen on fixed gear track (velodrome) bikes, a flip flop hub is hub that allows a cog to be attached to each side.

This allows a rider of a fixed gear bike to effectively 'change' gears by taking the rear wheel off, flipping it around and reattaching the wheel.

Track riders will use this to have a smaller (more teeth, fewer gear inches) warmup gear that allows them to spin at a higher cadence and a larger (fewer teeth, more gear inches) cog for racing or high speed efforts.

Variations of flip-flop hubs might offer a freewheel in one direction and a fixed gear in the other, so a cyclist can convert the bike from a single-speed to a fixed gear bike by flipping the rear wheel around.

More information: http://en.wikipedia.org/wiki/Flip-flop_hub

Answer 30

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).