High-Tensile
Steel Less-expensive, heavier form of steel frame material, often found in lower-priced bicycles.

Freestyle
Trick-oriented riding with specialized frame and component designs. Flatland (as the name implies) and vert (on wooden ramps, often shaped like half-pipes) are the two subcategories of freestyle bicycling.

Gussett
Frame reinforcement, generally welded on at high-stress joints.

Pegs
Cylindrical attachments on a BMX bike’s axles used for grinding on ramps and rails and also for standing on for a variety of freestyle tricks.

Threadless
A threadless fork has a smooth, unthreaded top (known as a steerer tube) that allows handlebar stems to be changed more easily than older, threaded forks permitted. Most modern bicycles offer threadless forks, which don’t offer major performance enhancements, but are welcome for those who like to do mechanical work on their bikes themselves.

Vert
Short for vertical, referring to the vertical tops of trick ramps.

Chrome-Moly
A lightweight steel alloy named for two of its components, Cromium and Molybednum. The chrome-moly alloy known by the designation 4130 is the most popular variety and the most common frame material among BMX bikes, though lighter aluminum tubing is often found on racing bikes.

Dirt Jumping
Getting airborne on a BMX (or mountain) bike, generally on a specifically designed course, but outside of the racing context.

Dropouts
The rear portion of all bicycle frames, designed to accept the rear wheel’s axle. Large or thick dropouts should accompany BMX bikes, which are meant to withstand the stresses of jumps and torque caused by the use of freestyle (or grinding) pegs.

Cruiser Class
BMX racing class that uses larger 24-inch-diameter wheels. Cruiser class riders tend to be older, bigger racers or parents participating with their kids.

Detangler
Rotor that attaches to the bicycle’s stem and allows the handlebars to be spun a full 360 degrees for tricks without tangling up the brake cables.