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
Belt-driven bicycle which allow riders of belt-driven bicycles to shift easily) are constantly innovating and introducing new designs such as the Shimano Alfine 11 and Fallbrook Technologies’s NuVinci. Other major internally geared hub makers include SRAM, Sturmey-Archer and Rohloff. Another option to provide gears is using a bracket-mounted gearbox like the Pinion P.18. manufacturers of belt-driven bicycles or belt drives include: Belt-driven bicycle A belt-driven bicycle is a chainless bicycle that uses a toothed synchronous belt to transmit power from the pedals to the wheel. The belts are typically made by the same manufacturing companies that produce timing belts for automobiles, machinery,