Take the tire size185/60r1491v as an example:
185 means that the tire width is185 mm; ; 60 indicates that the percentage of the height and width of the tire cross section is 60%, that is, the flattening rate of the tire; R stands for meridian, which means radial tire; 14 means that the rim diameter is 14 inch; 9 1 represents the load index of the tire, or the load index; V represents the speed level of the tire.
Tire size can be expressed in many ways, including English, German, Metric and American.
The former vassal States of Britain adopted the British standard, with the unit of inch. For example, 4.00H- 18-4PR means 4 inches wide, which is suitable for speeds below 210 km/h/h. The tire rim has a diameter of 18 inches and has four layers of strength. In the metric notation, the tire characteristics are described completely, which is similar to the German notation, but the mark of-low pressure tire is cancelled and the radial tire is replaced by R. For example, the rear wheel of FZR400 is 140/60R 18-64H, where R 18 indicates that the tire is a radial tire.