Suspension fork
Components 101: Suspension Fork
Suspension forks are now commonplace on mountain bikes and available on some hybrid bikes. Here are three important key terms to consider:
(1) Travel - this is the amount of movement in the suspension fork when pressure is applied. Travel can be externally adjusted by turning a knob on top of one of the legs on more expensive forks. In mountain biking greater travel is beneficial for riding downhill, but less for climbing.
(2) Rebound - this is the rate at which the suspension fork bounces back after it has been depressed. This can be adjusted on most forks to alter the feel of the bike.
(3) Lockout - this turns off the suspension so there is no travel whatsoever. Some mountain bikes do this for road use or when climbing as it can make the bike more efficient.

