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
Bicycle helmet laws by country Poland but it was opposed by cyclists' organisations. Bicycle helmet laws by country The wearing of bicycle helmets, and attitudes towards their use vary around the world. Compulsory use of helmets has often been proposed and is the subject of much dispute (see Bicycle helmet laws), based largely on considerations of overall public health. Only two countries (Australia and New Zealand) currently require and enforce universal use of helmets by cyclists. In some other jurisdictions, partial rules apply - for children, in certain states or sub-national areas, or under other limited conditions. Denmark and the Netherlands have a strong cycling