An average mountain bike has several additional features compared to a regular bicycle. These include larger number of gears, knobby tires, a wider handle bar and often some form of suspension for the tires. A mountain bike skeleton is called a chassis, a term that refers to the frame, fork and suspension as one unit. A chassis is generally constructed using lightweight materials such as carbon fiber.

These bikes are often equipped with a large number of gears, with some models being equipped with as many as 27 gears. The lower range of gears helps mountain bikers climb steep hills or obstacles. Mountain bikes use sprocket technology that makes changing gears easier, and shift levers that automatically move up or down, one gear at a time.

A mountain bike usually has both a front and a rear suspension. The suspension acts as a shock absorber for both the rider and the bike. Based on the type of suspension, mountain bikes can be classified into three main categories: Hardtail (frame with no rear suspension, often has a front suspension fork), Fully Rigid (sub-type of hardtail, with a rigid fork) and Dual or Full suspension (front suspension fork and rear suspension integrated into the frame).

Some mountain bikes may also be fitted with bar ends on the handlebars, especially in the case of flat straight handles bars. However, with an increasing preference for riser handlebars, bar end extensions are being used in smaller numbers. These bikes are commonly available with a wheel size of 26 inches (660 mm). Recently, larger wheel sizes of 29 inches (737 mm) have also been introduced. The larger wheels usually roll better over obstacles, but they reduce the maneuverability of the bike.

While a variation of the cantilever brakes is found on most mountain bikes, some of these, especially those with suspension systems, have disc brakes. With a large choice in parts available for mountain bikes, it is important to research your requirements, before shopping around to get the best prices.