
While it is certainly possible to design a recumbent mountain bike, they are usually severely limited in their off-road capabilities. At best, they can be used for riding unpaved roads, and an occasional trail. However, the position of the rider and the longer wheel base makes them unsuited for any trail that requires tight cornering and aggressive maneuvering.
A recumbent mountain bike, however, can be a much more comfortable way to enjoy an easy ride on a dirt road. The laid-back riding position combined with a back-supporting seat makes these bikes very comfortable. This is especially true on long rides.
There are a few companies that make a recumbent mountain bike, but most are created by the riders themselves. They are most often made from a modified recumbent that is designed for road use. These modifications often include switching to off-road tires, and the use of a more mountain-friendly gearing system.