There are three main type of bicycle tires. The first type of bicycle tires (which are also the most common) are clincher tires which are easily mounted on wheels and use an inner tube to maintain air pressure. The second type of bicycle tires are UST tires which, when mounted to UST wheels, form a completely tubeless system. The third type of bicycle tires are tubular tires commonly used on high performance road bicycles. Unlike clincher or UST bicycle tires, tubulars are completely closed and are glued on the rims of tubular specific wheels.