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
Trek Bicycle Corporation subsidiary of Roth Corporation, a Milwaukee-based appliance distributor. In early 1976, with a payroll of five, Trek started manufacturing steel touring frames in Waterloo, Wisconsin, taking aim at the mid to high-end market dominated by Japanese and Italian made models. Trek built nearly 900 custom hand-brazed framesets that first year, each selling for just under $200. Later that same year Trek Bicycle was incorporated. In 1977, Penn Cycle in Richfield, Minnesota became the first Trek dealer in the world. Within three years, Trek sales approached $2,000,000. Hampered without additional manufacturing capacity, Trek sales plateaued in the late 1970s. In just