As an avid cyclist, one question that I've been asked quite a number of times, is what the main differences between a mountain bike and a road bike are. Both forms of biking are very popular for entirely different reasons. You wouldn't think that a bicycle, as simple as it is, could have two entirely different variants, with two entirely different purposes. A mountain bike is designed, in a nutshell, for rough terrain and off-road use. A road bike is designed solely for on-road use. The main differences in design are in the suspension systems of the bike, however, there are other subtle details that really determine what the bike's usage should be.
The first thing I mentioned is the bike's suspension, which really determines whether the bike should be used on or off road. Road bikes generally have little to no mechanical suspension. Any suspension that they may have, is very unforgiving, and usually depends on the flexibility of the bike's frame. If you have a true road bike, you absolutely want to avoid riding it off road or on rough terrain, because it will be extremely uncomfortable due to the bike's inability to absorb terrain impact. Basically, you will experience a violently bumpy ride, with only a skinny bicycle seat making contact with your body's mass. Not very enjoyable at all.
However, a mountain bike is designed for off-road use and extreme terrains. A mountain bike utilizes either one or two suspension systems. These suspension systems are generally either shocks, springs, or air hydraulics. Some mountain bikes only have front suspension shocks, while other mountain bikes have front suspension shocks, as well as a rear spring or hydraulic for the real wheel. Generally the more suspension you have, the more comfortable your ride will be.
