BMX DICTIONARY FOR BEGINNERS
4130, CHROMO OR CHROMOLY
Refers to 4130 Chromoly, a strong metal alloy used abundantly in the production of BMX bicycles and parts.
20’S:
Twenty-inch bicycle wheels, the most common size wheel for BMX bicycles.
AXLE:
The shaft on which the wheel revolves.
BARS:
An abbreviation of handlebars.
BERM:
A corner on a track built up on the outside of a turn to create a banked curve.
BMX:
Abbreviation for bicycle motocross.
BOTTOM BRACKET:
The mechanism at the bottom of the bicycle frame, which holds the spindle and crank.
BRAKES:
Any bicycle braking system which works by opening and closing two brake shoes on the rim in a clamping motion, like jaws.
BRAKE LEVER:
A lever mounted on the handlebar used for activating the brake.
BUNNYHOP:
Riding along and lifting both wheels off the ground, the starting point for almost all BMX tricks.
CASE:
Coming up short on a jump & the back wheel of the bike hits the peak of the landing.
CHAIN STAY:
The part of the bicycle frame that runs parallel to the chain. It connects the bottom bracket to the rear dropouts.
CHAIN WHEEL:
A one-piece front gear. The chain wheel is attached to the bottom bracket and crank.
CLIPLESS PEDALS:
Hook or “clip” to your clip less shoes. Some clipless pedals have a cage around the outside of the pedals.
CRANK:
The L-shaped metal arm to which the pedals are attached.
CRUISER:
A Bicycle with 24” wheel diameter.
DEAD SAILOR:
A jump that goes wrong where the rider goes stiff and lands without performing a trick
DOUBLE:
A form of ramp consisting of a separate launch and landing with a gap in between
DOWN TUBE:
Part of the bicycle frame, which slants downward at an angle. It runs from the head tube to the bottom bracket.
DNS:
Designation on a moto sheet that a rider “Did Not Start” in any particular race.
DRIVETRAIN:
The assembly unit on a bicycle consisting of the chainwheel, chain, and freewheel.
DROPOUTS:
Small, slotted openings, which hold the front and rear wheel axles.
EXPERT:
Highest level of amateur competition.
FRAME:
The main part of a the bicycle, on which all the smaller parts are attached. Consists of a top tube, down tube, seat stays, chain stays, seat tube, and head tube.
FORK:
The double-pronged section of the frame, which holds the front wheel in place.
FREEWHEEL:
A one-piece rear gear that allows the rider to back-pedal. Bearings are built in.
GEAR RATIO:
A number, which indicates the relationship between the two gears and tells you how much work a particular combination of gears will do.
GRIPS:
Rubber or Plastic cover who goes on the handle bars at the end to aid in grip.
HEADSET:
Bearing set for which your front end rotates on and your fork/handle bars slide into.
HEAD TUBE:
A short vertical tube at the very front of the bike. The front fork fits inside the head tube.
