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 Stumpjumper in full (front and rear) suspension and hardtail (front suspension only) options, with the former named the Stumpjumper FSR. Professional mountain bikers who ride Stumpjumpers include Christoph Sauser and Ned Overend. Overend won the 1990 Mountain Bike World Championships – the first ever event of its kind – on a carbon-fiber prototype Stumpjumper. Specialized Stumpjumper The Specialized Stumpjumper is a mountain bike produced by Specialized Bicycle Components. When it was first produced in 1981, the Stumpjumper was the first mass-production mountain bike. The Stumpjumper is still in production, although its design has changed significantly since it was first sold. Stumpjumpers