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 for Trek, marking the year that the company unveiled its first molded carbon fiber frame, the Trek 5000. The 5000 frameset (monocoque carbon frame plus bonded aluminum fork) had an advertised weight of . Designed by Trek but built by Brent Trimble, an outside manufacturer, the 5000 suffered enough quality problems that it was discontinued after just one year. But the lessons learned from the 5000 would prove to be instrumental in driving Trek to develop its own carbon manufacturing capabilities in the coming years. In 1990 Trek developed a new category of bicycle that combined the comfort features of