Single-speed bicycle on the situation, a messenger may prefer a mountain bike based single-speed, which can roll over many obstacles, or a fast and light road bike-based single-speed. In the United States market, bicycle companies such as Bianchi, Cannondale, Fuji Bike, KHS, Kona, Raleigh, Giant, Specialized, Swobo, Felt, Trek and Niner all have produced and marketed single speed bicycles. Because most full suspension frame designs either have a single pivot that is not concentric with the bottom bracket, or a linkage with a variable center of rotation, the distance between the bottom bracket and rear axle varies throughout the suspension's travel. This
Specialized Bicycle Components Specialized issued a recall on about 12,000 bicycles sold through retailers from 2007 until July 2012 for a faulty front fork. Recalled models include the company's "Globe" products. A customized version of the Specialized Rockhopper mountain bike is currently used by the London Ambulance Service to equip their Cycle Response Units which operate in congested areas of the city. In 1990, Specialized tried to sue RockShox Inc, claiming the company's name too closely resembled the bicycle model name "Rockhopper" The case was ultimately dismissed with prejudice. In 2006 Specialized sued Mountain Cycle over its use of the model name "Stumptown"