The Ultimate Bicycle Glossary

Air Pressure – Measured in PSI, it refers to the amount of compressed air in a bicycle tire.
Allen Head – Hexagonal hole into which an “Allen wrench” is inserted to turn the bolt or screw.
Align – Usually used to refer to a bicycle wheel, it’s to make it on-plane and round.
Alloy – In the world of bicycling, it means aluminum alloy, which is more malleable and stronger than pure aluminum.
Axle – The shaft on which a turning article is mounted.
Axle Nuts – Used to secure a bicycle wheel onto a bicycle.
Back Bar – Almost like a Sissy bar, only shorter.
Ball Bearing – Used to reduce friction, it’s a kind of bearing whereby rolling balls connect the turning part to the non-turning part.
Basket – A fitting to carry things on a bicycle.
Bike Bearing – This is another term for Ball Bearing.
Bell Crank – The link between Shimano’s 3-speed hub and the control cable.
Blowout – The bursting of a bicycle tire.
Bolt – The metal rod which is screwed into a nut.
Bottom Bracket – The section of the bicycle where the crank bearing set is located.
Brake – The device used to stop the bicycle.
Box-end Wrenches – A spanner with 6-point or 12-point socket, used to secure a nut or bolt.
Brake Arm – The arm attached to the chain stay to prevent damage to the bicycle frame or hub bearing adjustment when the coaster brake is activated.
Brake Lever – The lever used to control the brake.
Brake Quick Release: A device to cause brakes to open more so as to facilitate the installation and removal of wheels.
Brazing – Similar to welding, it’s a type of hot gluing.
Bridge Wire – Attached to the main brake cable, it’s a short cable used to join the dual parts of the cantilever brake together. 
Cable – In bicycles, it refers to a mechanical control conduit.
Caliper Brake – A brake that clamps the side of a wheel’s rim to stop it from rotating.
Centerbolt – Axle on which a sidepull brake is mounted and pivoted.
Centerpull Brakes – A caliper style braking system commonly used on bicycles with thin tires.
Centerpunch – An apparatus used to mark drill holes in metal, much like a hard nail.
Chainguard – A covering over the chainwheel and chain to protect the rider.
Chain Link – Segment of a chain.
Chain Lube – Lubrication for bicycle chains.
Chain Skip – Skipping of chain link when pedaling hard.
Chain Tension – Refers to the tightness of the chain around the chain wheel.
Chainwheel – Another term for the front sprocket, it’s a toothed wheel around which the chain runs.  
Cleat – Plate found under special cycling shoes for better attachment to the pedal.
Coaster Brake – Brake constructed within the center of the back wheel.
Coasting – Riding the bicycle without pedaling.
Combination Wrenches – Contain box and open on each end.
Cottered Cranks – The system whereby tapered flat side steel bolts hold the cranks to the axle.
Cyclometer – A meter that showing how much distance has been covered by the bicycle.
Deflection – The bending of parts of bicycle as a result of the force of riding.
Degreaser – A chemical substance which is effective for cleaning grease on bicycle.
Derailleur – A mechanism that makes it possible for the bicycle chain to move from one sprocket to another during gear change.
Dish – To shorten the spokes on the right side of rear hubs so the rim can be centered.
Eccentric Chainwheel – Chainwheel which is not totally round.
Enamel – Durable, but slow-drying type of paint.
Extension Lever – Brake lever extension for bicycle with downturned, racing-style handlebar.
Ferrule – Tiny cap to prevent the fraying of end of inner cable wire.
Fixed Gear – Rear sprocket mounted to the wheel so it’s impossible to coast. In this way, the rider can reverse the bicycle. 
Flanges – Outermost portion of a wheel hub.
Flat Spot – In reference to bicycle wheels, it’s condition whereby the radii of a part of the wheel are somewhat shorter.
Flat Tire – Tire puncture.
Floating Adjustment – Refers to an unpredictable adjustment.
Foam Grips – Grips made of foam for more comfortable handling.
Footpegs – Special devices fitted on wheel axles to support rider’s foot.
Fork Blades – Twin tubes of a fork where the front wheel is attached.
Frame – Skeleton of the bicycle.
Fraying – Unraveling of a control cable’s inner wire.
Free Mount – To mount and ride a bicycle without using a fence or pole for support.
Freewheel – The mounting of one or more sprockets around the bicycle’s rear wheel hub.
Friction Bearing – Bearing used in most derailleur pulleys.
Front Derailleur – Device to control the chain among a number of chainrings.
Gearing –Increase in speed of rear wheel in relation to sprockets being larger at the crank in comparison to those in the rear hub. 
Generator Set: Dynamo powered set used to power a light bulb.
Grease – Lubrication without drip.
Guide Pulley – Top small wheel on rear derailleur functioning to reduce excess chain slack.
Gumwall Tires – Tires with sidewall of natural rum rubber, or tire with synthetic sidewall which appears like gum rubber.
Handgrips – Provide a comfortable and safe place for riders to place their hands on the handlebars.
Handlebar – A metal bar usually made of aluminum alloy or steel over which the handgrips are attached.
Handlebar Stem – Metal part connecting the fork and the handlebar.
Headtube – Bicycle frame’s front tube where the fork is mounted.
High Gear – By using large sprocket at crank to rotate small sprocket on rear wheel, the speed of bicycle is increased, but it’s harder for rider to pedal.
Hub – The center of the wheel, comprising axle and bearings.
Hub Shell – Also known as the hub body.
Indicator Chain – Refers to small chain protruding out of axle nut of 3-speed, 4-speed, and 5-speed Sturmey-Archer and Suntour wheels.
Inflation – Quantity of compressed air in tire.
Inner Tube – The rubber tube used as air seal inside a bicycle tire.
Kickstand – A bicycle accessory which makes it possible for a bicycle to be parked upright.
Kink – Bend in a rim as a result of hitting a solid obstacle.
Lacquer – Quick-drying semi-transparent thin paint.
Lathe – Precise machine for shaping metal.
Left-Threaded – Nuts and bolts with reverse thread.
Lock Nut – Thin nut on hub axle preventing the bearing cones from altering their adjustment.
Low Gear – By using small sprocket at crank to rotate a big sprocket on rear wheel, the speed of bicycle is reduced, but it’s easier for rider to pedal.
Lubrication – The process of using oil or grease to reduce friction among metal parts in bicycle.
Needle Bearing – A form of roller bearing where rollers are thinner than their length.
Non-Friction Bearing – Use of ball bearings to ensure rolling contact in all movements; effectively reducing friction.
Non-Turn Washer – Unique washer used on axles of specialized hubs with planetary gear sets to stop them from rotating within the dropouts.
Nut – Fastening device to be used with bolts.
Odometer – A meter showing the distance a bicycle has traveled.
One-Piece Crank – A large dog-leg shaped steel bar acting as cranks as well as bottom bracket spindle, also known as American Crank. 
One-to-One Gear – Sprocket at cranks and rear wheel are the same size so one crank revolution equals to one rear wheel revolution.
Patch Kit – A kit to patch flat tires.
Pawl – Small flipper that makes clicking sound in freewheels.
Pedal – Mounted at the crank, this is the device the rider places the foot to rotate the crank.
Pedal Wrench – Long thin wrench to install and remove the pedal.
Pivot – Hinge which allows bicycle component to swing.
Planetary Gearing – System with more than one gearing, usually built in the rear wheel hub.
Presta Valve – Valve typically found in sew-up tires and the inner tubes of thin tire bicycles.
Pre-Stressing – The practice of relieving the stress in a newly trued wheel.
Quick Release Brake – Another term for Brake Quick Release
Quick Release Skewer – A long rod with cam-action lever and threaded knob on each end, used to fasten the wheel onto bicycle.
Ratchet – Technique whereby the cyclist pedals forward and backward, applying partial strokes.
Reaction Arm – Another term for Brake Arm.
Rear Derailleur – Operated by cable, this mechanism allows the rider to guide the chain between sprockets on the rear freewheel. 
Recumbent – Close-to-ground bike for lower center of gravity and reduced wind resistance.
Right-Threaded – Nuts and bolts threaded in normal way.
Rim – Metal ring holding the tube and tire.
Road Bike – Bicycle specially built for most efficient riding on the road; typically with light weight large frame and thin tires.
Rotor – Special device around the handlebar that allows freestyle bikers to turn the handlebars many rounds without twisting up the rear brake cable.
Safety Lever – Similar to extension lever.
Safety Washer – Plate that ensures the front wheel will still remain with the bicycle even when the axle nuts have fallen off.
Sealed Bearing – Neoprene sealed bearing which prevents dirt and moisture from entering.
Seat Pin – Another term for seat bolt; the bolt that prevents the seat post from gliding down the bicycle frame.
Seat Post – The tube where the seat is mounted.
Seat Tube – The bicycle frame tube which fits the seat post.
Shifter – A mechanism which enables the rider to shift gears by using the hand.
Sidepull Brakes – A kind of caliper brakes with pivot on central axle.
Spokes – Thin metal rods for the purpose of holding wheels together.
Sprocket – Toothed wheel to hold a chain.
Suspension – A system which makes use of compression mechanisms to soften a bicycle’s ride.
Tension Pulley – Found on a rear derailleur, it’s the lower pulley.
Tire Lever – A special tool used to remove tires from rims.
Toe-In – Adjustment on brake pads so only the trailing edges are in contact with the rim when brake is used lightly and the whole pad is in contact when the brake is used more heavily.
Torque Wrench – Tool that allows the user to gauge the amount of torque to be used on nuts and bolts.
Trigger Shifter – Usually mounted near the grip on the handlebar, this device is operated by thumb.
Truing Stand – A device is used to secure the bicycle wheels so that they can be aligned.
Universal Brake Cable – As the name implies, it’s a brake cable which can be used on most kinds of brakes.
Universal Derailleur Cable – Derailleur cable which can be used on most kinds of derailleurs.
Valve – The device through which air enters or exits the bicycle wheels.
Washer – Flat metal ring used to spread the squeezing force exerted by bolts and nuts over a wider area.
Wheel Alignment – The condition of the wheel manifested in these qualities: lateral, plane, and round.
Whitworth – Rarely used British Empire bicycle dimensioning standard.
X-Wrench – X-shaped wrench with four socket openings
Y-Wrench – Y-shaped wrench with 3 socket openings
Yoke – Small metal plate used on almost all center-pull and cantilever brakes for fixing the inner wire of main brake cable to straddle wire. Also known as a cable carrier, it has an anchor bolt and a hooked surface.

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