The six digits of the tire are on the side of the tire, and the shape of most tire model signs is like 2 15/70R 15. The meanings of these numbers are 2 15, respectively, indicating the tire section width in mm. Generally, the tire width is between 145 and 285mm, and the interval is10 mm. 70 is the flattening rate, that is, the ratio of the tire sidewall height to the tire section width. Tire is the general name of tire, usually made of wear rubber material, which is divided into solid tire and pneumatic tire, and consists of inner tube and outer tire.