"Mountain biking is an exciting sport that involves riding bicycles anywhere off paved roads. it is roughly broken down into three categories: cross country, downhill, and free riding. However all mountain bikes have a somewhat similar look, knobby tires, large round tubing, and usually some sort of suspension or shock absorbers. Mountain biking can be done anywhere from a back yard to a gravel road, but the surface of choice is tight, twisting, hilly, rocky trails known as single track."
Thought this was an excellent description of mountain biking!
The very basic.
Dwight