If you want to roughly classify Motorcycle tires, they can be divided into tires with inner tubes and tires without tube (usually called tubeless tires by car mechanics). Tubed tires work by keeping air inside the tube and do not require precise contact between the tire and the rim. Even if the air pressure is low, there is no need to worry about the tire falling off the wheel and causing a leak. Therefore, tube tires are commonly used on off-road vehicles and American street cars that use rims and wires. The principle of tubeless tires is to use the special structure of the rim of the steel ring (rim) and the edge of the tire to seal the air in the carcass. Even if the tire is punctured by a foreign object, the air will not disappear immediately, and the puncture repair is also very convenient, so it is very popular among motorcycle riders. In recent years, tubeless tires have gradually been used on ordinary motorcycles. It can be seen that the two types of tires have their own strengths.
Generally, qualified Motorcycle tires are marked with the size, maximum load, internal inflation pressure, standard rim and brand name and direction. For example, the outer tire is marked with a specification of 90/90—18 51S, of which the first 90 means the width is 90mm; the 90 after "/" means the flat ratio (%), that is, the height is 90% of the width; 18 means the inner diameter of the tire is 18 inches (1 inch = 2.54cm),
Some tires do not indicate the flat ratio, which means that the flat ratio is 100%, that is, the width is equal to the height.
