Fatbike
Appearance
A fatbike is a bicycle with over-sized tires, typically 3.7" or larger that are designed for riding on soft unstable terrain such as snow and sand. These bikes are built around frames with large forks and stays to accommodate the wide rims required to fit these tires.
Usage
Fatbikes were invented for riding on snow and that is their most common usage, however their utility has expanded to include sand and desert riding, bogs and mud as well as riding that is considered normal mountain biking.