A motorcycle fork is a component that connects the front wheel of the bike to the frame of the motorcycle. It is used as part of the steering mechanism that allows the user to turn the front wheel, and in most cases it is used as a shock absorption system. Modern versions of the motorcycle fork work on a hydraulic system, though some older systems use coil springs to absorb shock. The motorcycle fork plays an important role in the stability of the motorcycle, especially during braking, when the weight of the motorcycle and rider is likely to dive forward, increasing the risk of a loss of control.
Hydraulic versions of the motorcycle fork use a viscous fluid contained in long cylinders to absorb shock. The fluid can move through chambers within the fork, and depending on the size of the openings within the fork, the rate at which the fork compresses and rebounds can be changed. The two legs of the fork are likely to contain such a system, though some forks use an air system in one leg and an oil system in another. The combined systems allow for adjustability and stability while riding. When the components of the fork are contained within the tubing, the system is known as a telescopic motorcycle fork. These forks are used most commonly on just about all styles of motorcycles.
A springer fork is another popular type of motorcycle fork, though its design is fairly antiquated. A springer fork's legs do not contain any suspension components. Instead, a coil spring is mounted externally, and the fork legs move independently when an impact occurs. The spring absorbs the shock and pushes to return the fork legs to the original position. Springer forks are also known as leading link forks, since a linkage system of more than one bar is used to absorb shock.
The rake of the fork, or the angle at which the fork sweeps away from the frame toward the front wheel, can have a significant impact on the motorcycle's handling. A long rake that increases the angle at which the fork sweeps away from the frame can make steering more difficult; long rakes are usually reserved for chopper bikes that are meant more for show. Tighter rakes translate into tighter steering, and racing bikes usually feature very tight rakes. Motocross bikes will feature a rake somewhere in between, as steering and maximum shock absorption are important during motocross racing.