There are many ways to express the specifications of tires, and there are generally four kinds on the market: British system, German system, metric system and American system. We will briefly explain the next four kinds. The specification of the British system is adopted by the former vassal countries of Britain, and the unit is inches. For example, 4.00 h 18 4pr means 4 inches wide, applicable to speeds below 210km / h, tire rim diameter of 18 inches and 4 ply strength. In the metric system, the description of tire characteristics is relatively complete. It is similar to the German system, but the sign of "-" low-pressure tire is cancelled, and the word "R" is replaced to represent radial tire. For example, the rear wheel of FZR400 is 140 / 60r18 64H, and the R of R18 means that the tire is radial tire. The German specification is similar to the "metric system". In addition to the tire width expressed in mm, the flat ratio of the tire is also increased. The inner diameter of the tire is still in inches, followed by the load index and speed mark. For example: 140 (tire width 140mm) \ 70 (flat ratio 70%) - (low tire pressure) 18 (inner diameter 18 inches) 66 (load index 66) H (speed mark below 210km / h).
