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 a mountain bike with the quick ride of a road bike: MultiTracks, Trek's first line of hybrid bikes, were born. That same year Trek also introduced its first line of kids’ bikes. In 1991 Trek opened its first company-owned retail store in nearby Madison, Wisconsin. In addition to showcasing a full line of Trek products, the Trek Store served as a hands-on sales training center for employees from Trek's headquarters who lacked retail experience. The store also provided an outlet for Trek to test merchandising and marketing ideas before expanding them to its network of independent bicycle dealers. In the