Mountain Bikes are meant to be taken off road so they usually have some suspension to absorb shock from the trail. There are hard-tails (which have front suspension only) and dual suspension bikes with front and rear. The knobby tires on mountain bikes can make them a little slower for city riding so we recommend getting a set of slick tires for in-town use. As with road bikes, the general rule of thumb is that as you go up in price the bikes are lighter and have higher-end components. Here are some recommendations: