A fat tyre cycle, also known as a fat bike, is a type of bicycle characterized by oversized tires, typically around 3.8 inches (97 mm) or wider. These bikes were originally designed for riding on soft, unstable terrain like snow and sand, where standard mountain bike tires would sink or become bogged down.

The wide tires provide better traction and stability, allowing riders to traverse through various challenging terrains with greater ease. Fat bikes have gained popularity not only for their off-road capabilities but also for their versatility in urban environments and bikepacking adventures.

The wide tires can be run at lower pressures, which provides a smoother ride by absorbing bumps and obstacles. This feature makes fat bikes comfortable for long rides and offers a level of shock absorption that can be beneficial on rough terrain.

While fat tyre cycle were initially designed for specific terrain types, they have evolved to encompass various styles and purposes, including commuting, recreational riding, and even racing.