Bicycle frame in the context of "Aluminium alloy"

A bicycle, also called a pedal cycle, bike, push-bike or cycle, is a human-powered or motor-assisted, pedal-driven, single-track vehicle, with two wheels attached to a frame, one behind the other. A bicycle rider is called a cyclist, or bicyclist.

The bicycle was introduced in the 19th century in Europe. By the early 21st century, there were more than 1 billion bicycles. Bicycles are the principal means of transport in many regions. They also provide a popular form of recreation, and have been adapted for use as children's toys. Bicycles are used for fitness, military and police applications, courier services, bicycle racing, and artistic cycling.

A bicycle wheel is a wheel, most commonly a wire wheel, designed for a bicycle. A pair is often called a wheelset, especially in the context of ready built "off the shelf" performance-oriented wheels.

Bicycle wheels are typically designed to fit into the frame and fork via dropouts, and hold bicycle tires.

A touring bicycle is a bicycle designed or modified to handle bicycle touring. To make the bikes sufficiently robust, comfortable and capable of carrying heavy loads, special features may include a long wheelbase (for ride comfort and to avoid pedal-to-luggage conflicts), frame materials that favor flexibility over rigidity (for ride comfort—though frame flexing can eventually lead to metal fatigue and frame failure, so newer frames are rigid), heavy duty wheels (for load capacity), and multiple mounting points (for luggage racks, fenders, and bottle cages).

A unicycle, also monocycle is a vehicle that touches the ground with only one wheel. The most common variation has a frame with a saddle, and has a pedal-driven direct-drive. A two speed hub is commercially available for faster unicycling. Unicycling is practiced professionally in circuses, by street performers, in festivals, and as a hobby. Unicycles have also been used to create new sports such as unicycle basketball and unicycle hockey. In recent years, unicycles have also been used in mountain unicycling, an activity similar to mountain biking or trials.

Bikepacking is how a bicycle is packed for bicycle touring, and also refers to the adventure sport of long-distance unsupported cycle races. As with backpacking, lightweight packing is a popular topic within bicycle packing. Any kind of bicycle can be used for bikepacking, and specialized touring bicycles often have attachment points from the factory such as low riders and luggage carriers, but most types of bicycles can be equipped with a frame bag (attached inside the frame's main triangle), saddle bag (attached to the seatpost), top tube bag and handlebar bag.

Pedelec (from pedal electric cycle), or EPAC (electrically power-assisted cycle), or EAPC, is the term for electric bicycles or e-bikes where the electric motor is controlled by the rider's pedalling. In many countries this term describes the majority or all electric bicycles legally in use, but is not itself a legal description and as such seldom used. Many jurisdictions classify pedelec-type bicycles almost the same as unmotorized bicycles, with few or no legal restrictions, rather than as mopeds, where the riders are subject to the regulations of such motor vehicles, e.g. having a license, a vehicle registration, insurance, wearing a helmet, or age-restrictions.

The crankset (in the US) or chainset (in the UK) is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain or belt, which in turn drives the rear wheel. It consists of one or more sprockets, also called chainringsor chainwheels, attached to the cranks, also called arms or crankarms, to which the pedals attach. It is connected to the rider by the pedals, to the bicycle frame by the bottom bracket, and to the rear sprocket, cassette, or freewheel via the chain.

The bottom bracket on a bicycle connects the crankset (chainset) to the bicycle and allows the crankset to rotate freely. It contains a spindle to which the crankset attaches, and the bearings that allow the spindle and crankset to rotate. The chainrings and pedals attach to the cranks. Bottom bracket bearings fit inside the bottom bracket shell, which connects the seat tube, down tube and chain stays as part of the bicycle frame.

The term "bracket" refers to the tube fittings that are used to hold frame tubes together in lugged steel frames which also form the shell that contains the spindle and bearings; the term is now used for all frames, bracketed or not.

A bicycle fork is the part of a bicycle that holds the front wheel.

A fork typically consists of two blades which are joined at the top by a fork crown. The crown is often at the front. Most suspension forks have an arch connecting the two side of the lowers (the part connected to the axle.) It is often in front of the stanchions (shaft the lowers slide on) but not always. Above the crown, a steerer tube attaches the fork to the bicycle and the handlebars (via a stem) allowing the rider to steer the bicycle. The steerer tube of the fork interfaces with the frame via bearings called a headset mounted in the head tube.

A fork end, fork-end, or forkend is a slot in a bicycle frame or bicycle fork where the axle of a bicycle wheel is attached. A dropout is a type of fork end that allows the rear wheel to be removed without first derailing the chain.

Track bicycle frames have track fork ends, on which the opening faces rearwards. Because they do not have dropouts, the chain must be derailed from the sprocket before the rear wheel can be removed from a typical track bike. Some single-speed bicycles intended for street or trail use are also equipped with track fork ends instead of dropouts.

List of bicycle parts by alphabetic order:

• Axle: as in the generic definition, a rod that serves to attach a wheel to a bicycle and provides support for bearings on which the wheel rotates, for example a through-axle or an axle made for a quick release skewer. Also sometimes used to describe suspension components, for example a swing arm pivot axle
• Bar ends: extensions at the end of straight handlebars to allow for multiple hand positions
• Bar plugs or end caps: plugs for the ends of handlebars
• Basket: it is an optional attachment on a bike and is used for carrying things
• Bearing: a device that facilitates rotation by reducing friction
• Bell: an audible device for warning pedestrians and other cyclists
• Belt-drive: alternative to chain-drive
• Bicycle brake cable: see Cable
• Bottle cage: a holder for a water bottle
• Bottom bracket: The bearing system that the pedals (and cranks) rotate around. Contains a spindle to which the crankset is attached and the bearings themselves. There is a bearing surface on the spindle, and on each of the cups that thread into the frame. The bottom bracket may be overhaulable (an adjustable bottom bracket) or not overhaulable (a cartridge bottom bracket). The bottom bracket fits inside the bottom bracket shell, which is part of the bicycle frame
• Brake: devices used to stop or slow down a bicycle. Rim brakes and disc brakes are operated by brake levers, which are mounted on the handlebars. Band brake is an alternative to rim brakes but can only be installed at the rear wheel. Coaster brakes are operated by pedaling backward
• Brake lever: a lever for actuating a bicycle brake
• Brake shifter or colloquially, brifter (see also Shimano Total Integration, Campagnolo ErgoPower and SRAM Double Tap): combined shifter and brake lever control
• Braze-on: a fitting protruding from a frame to provide attachment, typically for cable housings or tire pumps and similar accessories
• Cable guide: a fitting below the bottom bracket which guides a piece of bare inner bowden cable around a corner
• Cable: a metal cable enclosed in part by a metal and plastic housing that is used to connect a control, such as a brake or shifting lever, to the device it activates
• Cartridge bearing: a type of bearing that is not user-serviceable, but must be replaced as a unit
• Cassette: a group of stacked sprockets on the rear wheel of a bicycle with a rear derailleur
• Coaster brake or backpedal brake
• Chain: a system of interlinking pins, plates and rollers that transmits power from the front sprocket(s) to the rear sprocket(s)
• Chainguard: Gear case cover for the entire chain either totally encasing (sometimes containing oil) or 'incomplete'. Either way, designed to keep clothing from fouling the chain. See also Skirtguard, Bashguard.
• Chainring: (one of the) front gear(s), attached to a crank
• Chainset: see Crankset
• Chainstay: a pair of tubes on a bicycle frame that runs from the bottom bracket to the rear fork ends
• Chain tensioner: a device to maintain proper chain tension
• Chaintug: a device to aid in setting the proper chain tension
• Cluster: a bicycle cogset, either a freewheel, or cassette
• Cogset: the set of rear sprockets that attaches to the hub on the rear wheel
• Cone: holds bearings in place, pressed against the cup
• Cotter: pin for attaching cottered cranks
• Coupler: to connect tubing together
• Crankset or chainset: composed of cranks and at least one chainring
• Cup: receives ball bearings which roll along its inner surface; integrated on most conventional hubs or can be pressed into older bottom bracket shells. See also Cone
• Cyclocomputer: an electronic accessory that measures and displays instantaneous and cumulative speed and distance. Often provides other measurements such as heart rate
• Derailleur: an assembly of levers, usually cable-actuated, that moves the chain between sprockets on a cassette or chainring assembly
• Derailleur cage: the part of the Rear derailleur that holds the Pulley wheels
• Quick release dropout: a piece on the rear dropout that the derailleur attaches to.
• Down tube: tube on the bicycle frame that runs from the head tube to the bottom bracket
• Dropout: a bicycle rear fork end that allows the rear wheel to be removed without first derailing the chain. The term dropout is often incorrectly used to refer to any fork end, but not all fork ends are dropouts
• Dustcap: any cap serving to keep dirt and contamination out of an assembly. Common over crank bolts, often plastic
• Dynamo: bicycle lighting component, also known as generator
• Eyelet:

• Electronic Gear-Shifting System: not simply a type of shifter or a type of derailleur, a complete system with switches instead of levers, wires instead of Bowden cables, and motor-driven derailleurs that must all work together
• Fairing: a full or partial covering for a bicycle to reduce aerodynamic drag or to protect the rider from the elements
• Fender or mudguard: curved pieces of metal or plastic above the tires which catch and redirect road spray thrown up by the tires, allowing the rider to remain relatively clean. May come in pairs
• Ferrule: a metal or plastic sleeve used to terminate the end of a cable housing
• Fork: a mechanical assembly that integrates a bicycle's frame to its front wheel and handlebars, allowing steering by virtue of its steerer tube
• Fork crown: the point at which the two blades of the fork meet below the steerer tube.
• Fork end: paired slots on a fork or frame at which the axle of the wheel is attached. See also Dropout
• Frame: the mechanical core of a bicycle, the frame provides points of attachment for the various components that make up the machine. The term is variously construed, and can refer to the base section, always including the bottom bracket, or to base frame, fork, and suspension components such as a shock absorber
• Freehub: a ratcheting assembly onto which a cog or cassette is mounted that allows the bicycle to coast without the pedals turning
• Freewheel: a ratcheting assembly that incorporates one or more cogs and allows the bicycle to coast without the pedals turning
• Gusset: plates added to the outsides of frame tubes to strengthen joints. These are more commonly seen on BMX and mountain bikes
• Hanger: part of frame or an attachment to the frame to which the derailleur is attached (see Derailleur hanger)
• Handlebar: a lever attached, usually using an intermediary stem, to the steerer tube of the fork. Allows steering and provides a point of attachment for controls and accessories
• Handlebar plug: see Bar plugs
• Handlebar tape: a tape wound around dropped handlebars so as to provide padding and grip, usually cork or cloth, sometimes foam rubber
• Head badge: manufacturer's or brand logo affixed to the head tube
• Head tube: the tube of a bicycle frame that contains the headset
• Headset: the bearings that form the interface between the frame and fork steerer tube
• Hood: the rubber brake lever covering on bikes with drop style handle bars
• Hub: the core of a wheel; contains bearings and, in a traditional wheel, has drilled flanges for attachment of spokes
• Hub dynamo: a generator inside one of the hubs for powering lights or other accessories
• Hub gear: a gearbox mounted inside the hub, 3-speed is common, 5, 7 are available ("Sturmey-Archer"), Enviolo makes a CVT, and Rohloff makes a 14-speed hub. Cable operated by one or two cables
• Indicator: a turn signal
• Inner tube: a bladder that contains air to inflate a tire. Has a Schrader, "Woods"/"Dunlop" or Presta valve for inflation and deflation
• Jockey wheel or Pulley wheel: one of two small sprockets of the rear derailleur that guides the chain
• Kickstand: a folding attachment used for assisting a bicycle to stand up on its own. Usually mounts to frame near bottom bracket, sometimes near rear dropouts
• "Lawyer lips": also called a "lawyer tab", a retention device on the dropouts of the front fork to prevent inadvertent loss of the front wheel in the case it is not properly secured
• Locknut: a nut designed not to loosen due to vibration
• Lockring: a ring, usually metal, of varying design, that serves to retain a component in place
• Lug: a metal connector used to align frame components where they join each other
• Luggage carrier: any accessory equipment designed to carry tools, gear or cargo
• Master link: a bicycle chain accessory that allows convenient removal and reconnection of an installed bicycle chain without the need for a chain tool
• Nipple: a specialized nut that most commonly attaches a spoke to a wheel rim. In some systems, it provides attachment to the hub
• Pannier: cloth zippered storage bags that mount to sides of luggage racks. Pronounced pan-ear, or pan-yer (an old English word, which is derived from an old French word)
• Pedal: mechanical interface between foot and crank arm. There are two general types; one secures the foot with a mechanical clamp or cage and the other has no connection to lock the foot to the pedal.
• Peg: short metal tube, about 6 inches (15 cm) long and 2 inches (5.1 cm) fastened to one or both ends of the wheel axles to either enable the rider perform certain tricks or provide a place for extra riders to stand or rest
• Portage strap: a strap (usually made of leather) attached to the inside of the bike frame, designed to make carrying the bike over one's shoulder easier
• Pulley wheel: see Jockey wheel
• Power meter: a device on a bicycle that measures the power output of the rider
• Quick release skewer: a skewer with a lever on one end that loosens when the lever is flipped. Used for releasing wheels and seat posts
• Rack: a rack that attaches behind the seat, usually with stays to the rear dropouts, that serves as a general carrier
• Reflector: reflects light to make bicycle evident when the illuminated by headlights of other vehicles. Usually required by law but held in disdain by many cyclists
• Removable training wheels: used for assisting balance. Comes in pair. Useful for first time bicyclists
• Rim: that part of a wheel to which the tire is attached and often forms part of the braking mechanism
• Rotor:

• Safety levers: extension levers, and interrupt brake levers. Used to apply brakes in order for the bicycle to slow down or suddenly stop
• Saddle or Seat: what a bicyclist sits on
• Seat rails: a metal framework over which saddle covering is stretched. The seat post attaches to the seat rails by means of a clamp
• Seat lug: a frame lug on the top of the seat tube serving as a point of attachment for a clamp to secure the seat post
• Seat tube: the roughly vertical tube in a bicycle frame running from the seat to the bottom bracket
• Seat bag: a small storage accessory hung from the back of a seat
• Seatpost: a post that the seat is mounted to. It slides into the frame's seat tube and is used to adjust ride height depending how far into the seat tube it is inserted
• Seatstay: frame components, small diameter tubes running from top of seat tube to rear dropouts
• Shaft-drive: alternate to chain-drive
• Shifter: gear shifting control
• Shock absorber: for bicycles with suspensions, a device that limits the rate at which suspension rebounds after absorbing an impact
• Side view mirror: aids in looking at the sides prior to moving slowly or turning to the left or to the right
• Skirt guard or coatguard: a device fitted over the rear wheel of a bicycle to prevent a long skirt, coat or other trailing clothes or luggage from catching in the wheel, or in the gap between the rim and the brakes
• Spindle: an axle around which a pedal rotates; threaded at one end to screw into crank arms
• Spoke: connects wheel rim to hub. Usually wire with one end swaged to form a head and one threaded end. A typical wheel has 36 spokes
• Speakers: loudspeakers specifically made for bicycles and/or strollers for cyclists and pedestrians with children to listen music or answer phone calls on their mobile devices when bicycling or transporting children. Both wireless and wired speakers are available to mount on their handlebars or frames. Even though speakers specifically made for bicycles are available to purchase, but depending on the sizes and shapes and the cyclists' ingenuities, any speakers can be strapped on to them typically by using silicone strappings. These speakers meant to eliminate the risks of using headphones such as obliviousness of incoming cars and other warnings, and continuous playing of music from them would also alert other cyclists and pedestrians nearby 
• Sprocket or cog: wheel with teeth that meshes with the chain; one of the wheels in the cogset or crankset
• Steerer tube: a tube on top of a fork that is inserted through frame and serves as an axle by means of which bicycle can be steered
• Stem: a bracket used to attach handlebars to steerer tube of fork. Usually secured by pinch bolts
• Tire: as in common usage. Usually pneumatic. A tubular tire is glued to the wheel rim; most tires use tubes, but tubeless tires and rims are increasingly common
• Toe clips: a metal or plastic cage attached to a pedal. Usually has an adjustment strap. Secures foot to pedal for increased control and more effective transfer of power from foot to drive chain
• Top tube: frame member leading from head tube to seat tube
• Valve stem or simply valve: port for adding or releasing air from the inner tube. Two types are commonly used: Presta and Schrader. A third type, the Woods/Dunlop valve, can still be found in Europe and Asia.
• Wheel: as in common usage. Traditionally and most commonly spoked
• Wingnut: for attaching wheels before the development of the quick release skewer

The headset is the set of components on a bicycle that provides a rotatable interface between the bicycle fork and the head tube of a bicycle frame. The tube through which the steerer of the fork passes is called the head tube. A typical headset consists of two cups that are pressed into the top and bottom of the headtube. Inside the two cups are bearings which provide a low friction contact between the bearing cup and the steerer.

A bicycle seatpost, seatpin, saddlepole, saddle pillar, or saddle pin is a tube that extends upwards from the bicycle frame to the saddle. The amount that it extends out of the frame can usually be adjusted, and there is usually a mark that indicates the minimum insertion (or maximum extension). Seatposts can be made of steel, aluminum, titanium, carbon fiber, or aluminum wrapped in carbon fiber.

A bottle cage is a device used to affix a water bottle to a bicycle. Composed of plastic, aluminum, stainless steel, titanium or carbon fiber, it is attached to the main frame of a bicycle, the handlebars, behind the saddle, or, in uncommon cases, the fork. Most modern bicycles have threaded holes in the frame to hold the bottle cage, often called braze-ons even though they may be welded, glued, riveted, or moulded into the frame material. Clamps are necessary on bicycles not so equipped, such as older or less expensive models.

In bicycling, a frame bag is a bag attached within the main triangle of a bicycle frame. They are used to add luggage capacity to your bike in a low-profile way without impeding on the ability to pedal and to distribute weight across the bike. Frame bags are common on touring bicycles, racing bicycles, and cross country mountain bikes. They're ideal for carrying tools, spare parts, electronics, snacks, and other items that may need to be easily accessed while riding. Frame bags help maintain a bike's center of gravity, improving balance and handling.

Frame bags can vary a lot, (2-10 litres) from small wedges designed to carry a few extra items on a ride to bags that completely fill the space within a bike frame's main triangle. They typically have multiple attachment points to all three frame members to keep it stable and in position. For attachment most bags use webbing although some bags and bikes feature braze-ons, enabling you to bolt a bag directly to the bike.