1. Rim width: Tongbai is usually expressed in 5.5J, 6J, 7J, and the unit is inch. Usually, the tire with a tire width of 185 needs a 5 inch rim width, 195 requires 6 inches, and 205 requires 6.5 inches. , 215 tire width needs to correspond to a 7-inch wide rim.
2. Rim diameter: There are 12, 13, 14, 15 and other specifications in units of inches. At present, commercially available vehicles have models equipped with 20 inch wheels, such as Infiniti FX35, BMW X5, etc.
3. PCD value: the diameter of the circle formed by the tire screws, the unit is mm, domestic cars are usually 100, 114.3, European cars are more special, including the 98 of love express, 108 of Volvo, 120 of BMW and M. Benz 112.
4. Center hole: to ensure that the geometric center of the rim can coincide with the geometric center of the hub, so that the steering wheel will not shake when the vehicle is running at high speed.
5. Geometric centerline: The most important reference data of the rim, including the calculation of the Offset value, the net value of the distance from the fender, etc., must refer to this value.
6. Offset: The distance between the fixed surface of the hub and the geometric center line, its most important role is to ensure that the tire will not wear the body.
7. Rim wall surface: used to support the tire tread and absorb the impact from the road surface.
8. The shoulder of the rim: tightly combined with the tire lip, providing good air tightness to establish tire pressure.
9. Rim disc surface: The claws of some rims will protrude beyond the vertical line of the disc surface, so that the rim cannot be protected by the tire, and it may hurt the rim surface coating when inadvertently parked.
10.X distance: data that must be taken into consideration when refitting multi-piston calipers, otherwise there may be friction between the rim disc surface and the brake calipers.