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
Giant Bicycles after workers at the Schwinn plant in Chicago went on strike in 1980, Giant became a key supplier, making more than two-thirds of Schwinn bikes by the mid-1980s, representing 75% of Giant’s sales. When Schwinn decided to find a new source and in 1987 signed a contract with the China Bicycle Company to produce bikes in Shenzhen, Giant, under new president Bill Austin (formerly vice-president marketing at Schwinn), established its own brand of bicycles to compete in the rapidly expanding $200-and-above price range. In 1984, Giant also set up a joint venture, "Giant Europe," with Andries Gaastra of Dutch bicycle