Belt-driven bicycle with a compact design that, like STRiDA, featured a belt drive. Other folding-bike manufacturers that have implemented a belt drive include U.S. company Bike Friday and Netherlands-based Bernds. In 2007, Gates Corporation developed a high-modulus synchronous belt and sprocket system called the Carbon Drive System. The belt’s pitch allowed for lower tension requirements to help prevent skipping. Lightweight, patent-pending sprockets have mud ports, openings under each tooth, which work to slough off debris. In 2009, an increasing number of bicycle companies, including Trek and "f"8 Cycles, offered belt-driven bicycles. While builders initially focused on single-speeds and internal hubs, in early
Tandem bicycle very same reason. Some argue that this produces a smoother power stroke, or that it reduces stress on the drive train because the point of maximum power is reduced to roughly half and distributed over the chainrings. Since the market for tandem bicycles is significantly smaller than the market for single bikes, there are far fewer tandem bicycle manufacturers than single-bicycle manufacturers. There are a few builders who specialize in tandems, as well as single-bike makers who offer tandem models. Current notable tandem bicycle manufacturers include: Tandem bicycle The tandem bicycle or twin is a form of bicycle (occasionally a