Friction drive

The Friction Drive The friction drive is another transmission found in some motorcycles. A friction drive is a type of continuously variable transmission, or CVT, in which the variation in gear ratios comes about as a disc connected to the engine (the driving disc) rotates across the face of a second disc connected to the rear wheel (the driven disc). By varying the radius of the contact point between the two disc surfaces, different gears can be achieved. Continuously variable transmissions have a long history of use in motorized vehicles, with variable friction transmissions appearing in motorcycles in the early 1900s.

motorcycles chassis

Frame
Motorcycles have a frame made of steel, aluminum or an alloy. The frame consists mostly of hollow tubes and serves as a skeleton on which components like the gearbox and engine are mounted. The frame also keeps the wheels in line to maintain the handling of the motorcycle.

Suspension
The frame also serves as a support for the suspension system, a collection of springs and shock absorbers that helps keep the wheels in contact with the road and cushions the rider from bumps and jolts. A swingarm design is the most common solution for the rear suspension. On one end, the swingarm holds the axle of the rear wheel. On the other end, it attaches to the frame via the swingarm pivot bolt. A shock absorber extends upward from the swingarm pivot bolt and attaches to the top of the frame, just beneath the seat. The front wheel and axle are mounted on a telescoping fork with internal shock absorbers and internal or external springs.