Front suspension is the most common form of suspension you will find on a downhill mountain bike. The front suspension on a mountain bike is affixed to the fork, the component which attaches to both the handlebars, allowing the rider to steer, and teh front wheel hub, allowing for control in the direction one is steering. On either side of the fork are tubes with the shock system of springs and dampers inside them. When the rider decides to steer their bike into an oncoming tree root, the wheels take the initial brunt of the collision - which is then transfered up the legs of the fork and quickly into the shocks, where the springs absorb the shock, allowing the wheel to bounce up an ddown, and where the dampers dissapate the majority of the impact. Many downhill front suspension systems rely on either oil or air shocks - dampers that release energy into and are lubricated by either oil or compressed air. Coil over oil shocks are more popular because the require lese maintainence and, unlike air shocks, can get wet and dirty and still work. Some greast shock and suspension brands are RockShox, Fox, and Noleen.