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
Bicycle suspension named "Split Pivot". Trek Bicycle Corporation also released a version of the split pivot design called "Active Braking Pivot" (ABP) in early 2007. Cycles Devinci has released a licensed implementation of the "Split Pivot" design which Dave Weagle managed to patent. "Horst Link" suspension is a type of four-bar linkage suspension. It is characterized by having both connecting links pivot on the seat tube, with the lower pivot located above the center of the bottom bracket, and the rear axle being located higher than the pivot connecting floating link and lower connecting link. Specialized has bought several of Leitner's patents