Glossary

Related Items:

Alloy: mixture of pure metals into a combined metal with altered characteristics.

BB: See Bottom Bracket

Bottom Bracket: This is the part that your cranks attach to that allows them to spin freely. A Bottom Bracket Assembly is usually composed of the crank spindle, bearings and bearing cups. All that stuff presses or threads in to the Bottom Bracket Shell which is part of the bicycle frame.

Bottom Bracket Shell: This is the fat stubby frame tube that your cranks sit in. There are two main styles of BB Shell, the "European" and the "American". European BB Shells are smaller, internally threaded and are found on road and mountain bikes. American sized BB Shells are larger, do not contain threads and are found primarily on BMX frames or really cheap frames that use single-piece cranks. A critical measurement in frame building is the "Bottom Bracket Height" which is measured from center to level ground.

Buddy Sticks: See "Pegs"

Cassette: A casette hub has the ratchet mechanism built into the hub shell so there is no need for a separate freewheel. Usually cogs of diferent sizes are available to modify gearing.

Chain Ring: AKA: sprocket, cog, star, chainwheel. A toothed sprocket that is attached to the crankset and drives the chain.

Chainstay: The chainstays are the two frame tubes that extend from the dropouts to the Bottom Bracket Shell area on either side of the rear wheel. The length of the chainstays from the center of the BB to the center of the rear axle is a critical frame measurement that partially determines how hard it is to initially pull up the front wheel. Shorter chainstay length makes it easier to pull up.

Chain Tensioner: Chain Tensioners are required equipment for most bikes with horizontal dropout slots. In BMX racing the force of the sprint gate start can move the rear wheel. In freestyle the repeated peg hits, especially icepicks, will do the same. Chain tensioners hold the rear wheel in place to keep your chain at the proper tension and prevent wheel slippage in extreme situations.

Cog: For front cog see "Chain Ring". For rear cog see "Freewheel" or "Casette".

Cranks: AKA: crankset or crank arms. There are two main types: single piece cranks(1-Pc) and three piece cranks(3-Pc). Single piece cranks are inexpensive and rather heavy. They get the job done on the majority of cheap single speed bikes. Single piece cranks are always made from solid steel and accept only 1/2" pedal spindles. Three piece cranks consist of two crank arms and one spindle. The aluminum or steel arms usually bolt on to the hardened steel spindle for a lighter and stronger crankset than a single piece setup. Three piece cranks accept only 9/16" pedals and are also usually more expensive. The cost difference can be as much as ten times more than single piece.

Down Tube: The Down Tube is the frame tube that extends down from the Head Tube to the Bottom Bracket Shell. It is usually the largest diameter tube on a frame.

Dropout: Dropouts in their most common forms are the slotted plates on your frame or fork that your wheels bolt into. They usually come in pairs and they can be found in the front or rear. Some dropouts have vertical slots and some have horizontal slots. They vary widley in shape, size, thickness and general design but they all provide a place to secure the hub axle in some way or another.

Freewheel: The Freewheel is a two part mechanism that is the rear cog fro the chain to ride on and it provides the necesary ratchet mechanism to allow pedaling and coasting.

Gauge: As it relates to spokes gauge is the English measurement of wire diameters. For example, 14 ga. = 2.0mm thick, 15 ga. = 1.8mm thick.

Hub: The Hub is the central element of a wheel that rotates on an axle and in which spokes are anchored.

Head Tube: The front tube on a frame that houses the headset and fork steerer tube. The Head Tube Angle is one of the main factors that determines steering quickness in a frame.

Nipple: Spoke Nipples are tubular threaded nuts used to tension spokes. There is one nipple for every spoke on the wheel.

Nutted Spindle: The reason why your cranks won't stay tight. The nutted BB spindle plagues mostly older cheap/mid priced bikes. Solution: Buy a spindle (or whole BB) that uses bolts that go in instead of nuts that go on to threaded studs.

Pegs: Pegs are used for two main purposes which are sometimes combined. One is to land on and grind them. The other is to stand on and balance. Grinding pegs are usually smaller and thicker while standing pegs are larger diameter for foot comfort.

Pogos: See "Pegs"

Presta valve: type of air valve used on high performance, narrow, roadie wheels. Uses a locknut instead of a return spring to keep valve closed. Although these valves are smaller, lighter and make less of a hole in the rim they are still annoying because getting air from a conventional source (gas station) requires a stupid little adapter.

Rim: peripheral part of a wheel on which the titre is mounted and the spokes are attached

Schrader Valve: the universal valve found on all car, truck, BMX tires.

Seat Guts: Inexpensive bikes and BMX/Freestyle bikes tent to come with Seat Posts that do not have integral clamps. These posts use Seat Guts which are a primitive 5-piece stamped steel clamp set held together by a double-ended bolt. The Guts is designed to simultaneously clamp the two seat rails and the top of the seat post. The downfall of the Seat Guts is its inability to hold the seat securely over long periods of time.

Seat Post: The Seat Post is the tube that supports the Seat and sleeves into the Seat Tube. Some Seat Posts have a clamp built-in to clamp the seat rails while others use separate Seat Guts.

Seatstay: The Seatstays are the two frame tubes that extend up from the dropouts to the Top Tube/Seat Clamp area on either side of the rear wheel.

Seat tube: The Seat Tube is a tube in the bike frame which accepts the Seat Post. It is important for the seat tube and the seat post to have precise corresponding sizes for a good fit while allowing smooth telescoping action for easy height adjustment.

Spokes: wire pieces that connect hub to rim

Sprocket: See "Chain Ring"

Top Tube: The Top Tube is the frame tube that extends horizontally from the Head Tube to the Seat clamp area. Top Tube Length is one of the critical measurements in frame building. It determines how much room the rider will have behind the bars and also the overall length of the frame.


Home Product Stickers Contact
Thick Bikes, 62 South 15th Street, Pittsburgh PA 15203 (412) 390-3590