Bike Glossary

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Aheadset ®
Dia Compe's trademark for threadless headsets
Air Spring
High pressure air reservoir used in a suspension fork or shock. Generally considered to be lighter, but not as plush as coil springs.
A metal that is a blend of various types of metals. In bicycle use, alloy generally refers to aluminum alloy parts
A lightweight and non-rusting metal that is used extensively for bicycle parts. Frames, and components such as rims, stems, handlebars, brakes and drivetrain components.
Acronym for All Terrian Bicycle. Generally ATB and MTB (mountain bike) are used interchangeably though ATB is much more common.


A bearing is the point of contact between a turning part and a non-turning part.
Acronym for Bicycle Motocross. BMX bikes are smaller, single-speed bikes made for people of all ages who enjoy riding, jumping or racing on dirt or riding on smooth surfaces. There are three major forms of BMX bikes BMX racing bicycles, Freestyle "stunt" bicycles and Dirt Jumping bikes.
Bottom Bracket
A bicycle component that consists of the crank axle (bottom bracket spindle) and ball bearings. Crankarms are bolted onto the bottom bracket.
Brakes - Coaster
A type of brake, used mainly on juvenile and Cruiser bikes that is engaged by pedaling backwards.
Brakes - Disc
A type of brake that consists of a rotor and a caliper. The rotor is bolted to the hub and the caliper holds brake pads that push into the rotor to slow the wheel. Disc brakes are generally more powerful than the type that operate on the rim and are better in adverse conditions. They can be either mechanical cable operated or hydraulic with oil running in a hose. Found primarily on mid and high priced mountain bikes.
Brakes - Linear Pull
This is the generic term for a V-Brake. The V-Brake name is a trademark of Shimano.
Brakes - V
A type of brake that contacts the rims, common on mountain, hybrid and juvenile bicycles. V-Brakes are powerful and relatively easy to set up and adjust. V-Brake is a trademark of Shimano, other companies refer to their brakes of this type as linear pull brakes.
Bicycle frame tubes that have thicker walls at the ends where they are welded to other frame tubes. Thicker tubing at the ends adds strength while thinner tubes in the middle portions help minimize weight and help improve ride comfort by minimizing vibration.


A disc brake component that holds the brake pads that contact the rotor in order to slow the wheel rotation.
A modern style of rear gear cluster that slides onto the rear hub. Cassette-style hubs are generally lighter than comparable freewheel gear clusters.
The key drivetrain component that circles the front chainring, the rear cassette and runs through the rear derailleur. Power is transmitted from the crankarms to the rear wheel through the chain.
The frame tubes that run horizontally from the bottom bracket shell to the rear dropouts where the wheel is attached.
Large sprocket(s) attached to the right crankarm which drive the chain.
Chrome Moly (aka CroMo, CroMoly, CrMo)
An alloy of steel and chromium and molybdenum. Stronger than hi-tensile steel, it can be drawn into thinner-walled tubes for lighter weight.
Coil Spring or Coilover
A coiled metal spring used in a suspension fork. Generally considered to be plusher, but heavier, than air springs.
Comfort Bikes
All-terrain bikes with ergonomically-superior upright riding positions, suspension forks, soft grips, cushy saddles and wide-range gearing; Comfort bikes generally use 26" mountain bike wheels.
The part of the crankset that the chainrings and pedals are attached to.
The drivetrain parts consisting of the crankarms and chainrings.
Cross Country
Also known as "XC", Cross Country bikes are jack-of-all-trades mountain bikes used either for racing or all-around trail use. Cross Country bikes are available either as hardtails or full suspension.
Classic styling, fat tires and general simplicity set these bikes apart from others. Cruisers offer wide saddles, upright riding positions and wide swept-back handlebars.


Front and rear gear changing devices that move the chain across the cassette and the front chainrings. Derailleurs are operated by pressing the shifters to move the derailleur cables.
Dirt Jumping
20" wheeled BMX bikes designed for use on dirt trails. Dirt Jumping bikes generally have 36 or 48-spoked wheels, a rear brake and semi-knobby tires.
Down tube
The portion of the frame that runs from the head tube to the bottom bracket shell.
Damping (or Damped)
A term used to describe the slowing down of rebound and/or compression of a suspension fork. Damped forks have a better feel than lower priced non-damped forks.



Part of the bicycle that holds the front wheel. The fork steerer tube is inserted into the head tube.
Fork - Suspension
A fork that is designed to absorb shocks using coil springs or air springs. Generally found on mountain bikes, comfort bikes and some hybrid bikes.
The basic element of the bicycle; tubes that form the backbone to which all of the bicycle components are connected. Frames generally have the following parts: head tube, top tube, down tube, seat tube, seat stay, chain stay and bottom bracket shell.
Mountain bikes designed primarily for downhill riding, but still have the capability to pedal uphill. Most freeride bikes have beefy full suspension frames with 6" or more suspension travel and disc brakes
20" wheeled BMX bikes designed for use on smooth surfaces ramps or street. Freestyle bikes generally have 48-spoked wheels, strong front and rear brakes and pegs to assist with performing stunts
An older style gear cluster that threads onto the rear hub body. Freewheels are generally less expensive and heavier than cassette gear clusters.
Front Derailleur
Bicycle component that moves the chain across the front chainrings thus changing the gear ratio and achieving what is referred to as a gearshift.
Full Suspension
Mountain bikes that have frames that allow both the front and rear wheels to move and absorb shock when they hit an object.


Gyro ®
The trademark name of the rotor manufactured by Odyssey.


The flat or riser bar that grips, brake levers, and shifters are attached to.
Mountain bikes that have a rigid (non-moving) rear end.
Head tube
Vertical frame tube onto which the top tube and down tube are attached. The fork steerer tube is inserted into the head tube.
Bearing component that secures the fork to the frame. Headsets can be either threaded or threadless.
High Tensile Steel
A type of steel used for bicycle frames.
Bicycle component located in the middle of the wheel from which the spokes radiate outward.
Also known as "city bikes", Hybrids have 700c wheels (approx 29" in diameter) with tires that are narrower than found on mountain bikes. Hybrids are similar to comfort bikes as they feature ergonomically-superior upright riding positions, suspension forks, soft grips, cushy saddles and wide-range gearing. Hybrid bikes are generally a bit more efficient than similar comfort bikes, but not quite as comfortable.




Kevlar ®
A very strong fiber, made by DuPont that is used in the construction of higher-end bicycle tires. Kevlar bead tires are also known as "foldable" tires and are, as the name implies, foldable. Kevlar tires are generally lighter than wire-bead tires.



Mountain Bike
Bicycles that are made primarily for offroad use and have 24" or 26" wheels and knobby tires.



Oryg ®
The trademark name of the rotor manufactured by SST.


Pedal (Clipless)
A pedal that engages with a special shoe by means of a cleat. With clipless pedals, the rider is attached to the bicycle until he or she twists their foot to unclip.
Pedal (Flat)
A flat-topped pedal that does not require any special shoe to use.
A type of valve used on high performance bicycle tubes



Rear Derailleur
Bicycle component that moves the chain across the rear cogs thus changing the gear ratio and achieving what is referred to as a gear shift.
The outer hoop of a bicycle wheel. The spokes attach to the rims via spoke nipples. Rims can be either steel, aluminum, or carbon fiber.
Riser Bars
Mountain bike handlebars that feature an upward sweep providing a more upright riding position and greater stability
Road Bike (Flat Bar or Comfort Road)
Bikes designed for road use, flat-bar road bikes have a more comfortable, yet less-efficient upright riding position more similar to a mountain bike than a traditional drop bar road bike. Great for use on charity rides.
Road Bike (Race)
Once referred to as "10-speeds", Road bikes are designed for use on hard surfaces, drop bar road bikes have skinny tires, lightweight frames and wide gearing ranges. Road bikes are the most efficient bicycles.
Rotor (aka Gyro ®, Oyrg ®)
A device, found on BMX freestyle or dirt jumping bikes, located just above the headset that allows the handlebar to rotate without the brake cable getting tangled up.
Rotor -Brake
A disc brake component consisting of a thin metal disc that the brake pads contact to slow the wheel rotation.


Cyclist's name for a bicycle seat.
A type of valve used on children's, BMX, and entry-level to mid-price adult bikes, these are the same type of valves as used on an automobile tire.
Since 1895, America's bicycle brand
Seat post
Frame component onto which the saddle is attached. The seatpost is inserted into the seat tube.
Seat stays
Paired frame tubes running from the seat tube to the rear dropouts.
Seat tube
Frame component into which the seat post is inserted.
The mechanism, generally found on the handlebars, that move shift cables which in turn move derailleurs in order to change gears.
Shifters - STI
STI refers to Shimano Total Integration. STI combination brake levers/ shift levers provide the ability to shift gears without taking your hands off of the handlebars
The rear vibration and bump absorbing unit on a full suspension bicycle.
Sidewalk Bikes
A child's first bike, these 12", 16" and 20" wheel bikes are great for beginner riders. 12" and 16" bikes generally come with kickstands while they are optional on 20" bikes.
Generally stainless steel, spokes are wires that connect the hub to the rim on a wheel
The component that holds the handlebars and mounts to the steerer tube.


Tire - comfort
Bicycle tires that have less-aggressive tread designs for smoother riding qualities on hard surfaces.
Tire - mountain
Mountain bike tires are size 26in. and are generally available in widths from 1 inch to 2.2 inches.
Tire - road
Modern road tires are generally size 700C. Road tires can also be found in the older less common size of 27in. These two sizes are not compatible and it is important to know which size tire is appropriate for your rims.
Top Tube
Horizontal frame tube running from the seat tube to the head tube.
Measurement of the total distance that a shock can travel
Rubber bladder inside the tire that hold air. Come in a variety of sizes, can be either Presta or Schrader. Ultralightrefers to a tube with thin walls.


A style of brake that push pads into the rim to slow the wheel. U-brakes are powerful and are generally found on freestyle and dirt jumping bikes.


V-Brake ®
Shimano's trademark name for linear pull brakes.


A wheel consists of a hub, rim, and spokes.
Wheels - Mountain
A wheel consists of a hub, rim, and spokes. Mountain bike wheels are size 26in.
Wheels - Road
A wheel consists of a hub, rim, and spokes. Modern road wheels are generally size 700C. Older road bike wheels may be 27in.
Refers to a pair of wheels, front and rear.