Fatbike

A fatbike (also called fat bike or fat-tire bike) is an off-road bicycle with oversized tires, typically 3.8 in (97 mm) or larger and rims 2.6 in (66 mm) or wider, designed for low ground pressure to allow riding on soft unstable terrain, such as snow, sand, bogs and mud. Fatbikes are built around frames with wide forks and stays to accommodate the wide rims required to fit these tires. The wide tires can be used with inflation pressures as low as 340 hPa (5 psi) to allow for a smooth ride over rough obstacles. A rating of 550–690 hPa (8–10 psi) is suitable for the majority of riders.

Fatbikes are also called "fat bikes", or "snow bikes". The sport is sometimes referred to as "fatbiking"

Fatbikes were invented for use in snow and sand, but are capable of traversing diverse terrain types including snow, sand, desert, bogs, mud, pavement, or traditional mountain biking trails. In several US states and provinces, fatbike-dedicated groomed winter trails have been created.

Although early versions of fat-tired bikes were probably built on a limited basis as long ago as the early 1900s, the first modern versions were not developed until the 1980s. An early example is the custom three-wheeled in-line longtail-style bike with fat tires, designed by French cyclist Jean Naud in 1980 for desert travel. He rode it from Zinder in Niger to Tamanrasset in Algeria, and later rode a similar bike in 1986 across the Sahara using fat tire prototypes from Michelin.

In the late 1980s, Alaskan frame builders began experimenting with custom components and configurations designed to achieve a large contact patch of tire on snow. Steve Baker, with Icycle Bicycles in Anchorage, was welding together two rims and even three rims and built several special frames and forks that could accommodate two or three tires together. In 1989, Dan Bull, Mark Frise, Roger Cowels and Les Matz, rode the 1,000-mile (1,600 km) length of the Iditarod trail.

Simultaneously, in New Mexico, Ray Molina had commissioned Remolino 3.1 in (79 mm) rims, 3.5 in (89 mm) tires, and frames to fit them. He wanted the bikes for his guided tour business in the soft sands of the Mexican and Southwest arroyos and dunes. Mark Gronewald, owner of Wildfire Designs Bicycles in Palmer, Alaska met Molina at the 1999 Interbike convention in Las Vegas and rode one of Molina's prototypes at demo days. In late 1999, Gronewald and another Alaskan frame builder, John Evingson, collaborated to design and build several bikes using Molina’s rims and tires. Gronewald and Evingson then began producing their own separate lines of fat-tired bikes in 2000. Rims and tires were imported to Alaska where Wildfire and Evingson began making small, handmade production runs and custom-ordered frames built around Remolino 80 mm (3.1 in) rims and 3.5-inch (89 mm) tires. Gronewald coined the trademark "Fat Bike" in 2001 and used it as the model name for his bikes. Gronewald originally worked with Palmer Machinery for welding and later contracted frame building to Mike DeSalvo at DeSalvo Cyles of Ashland, Oregon. Gronewald continued to sell his original fatbikes until 2011. Gronewald's design featured an 18 mm (0.71 in) offset wheel and frame built to allow full range gearing, since he was using standard hubs and bottom brackets available at the time.

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