The wheel hub is a cylindrical metal part with the inner contour supporting the tire and the center mounted on the axle. It is also called rim, steel rim, wheel and tire bell. There are many kinds of hubs according to their diameters, widths, forming methods and materials. The main parameters of automobile hub include: hub size, PCD, offset ET, center hole
1. The wheel hub size consists of two parameters: the diameter and width of the tyre ring. The representation is 15x6.5; 15x6.5JJ； 15x6.5J； 1565 and so on. There are no hard and fast rules on the format. The front "15" represents the diameter of the tire ring, which represents that the diameter of the wheel hub is 15 inches. The rear "6.5" (or 6.5J, 6.5JJ, 65) represents the width of the tire ring, which represents that the width of the wheel hub is 6.5 inches. The size of the hub can usually be found on the lettering on the back of the hub.
2. PCD: refers to the pitch diameter of hub bolt hole. For example, 5x114.3, 10x100/114.3, "5" represents the number of bolt holes, representing five bolt holes. "114.3" indicates that the pitch diameter of the bolt hole is 114.3mm.
3. Offset distance: (also called offset or ET) is the distance between the mounting surface and the center line of the hub. This parameter is usually found on the back of the hub. The offset is used to adjust the track width and ensure that the wheels do not interfere with the vehicle body.
4. Center hole: the large hole in the middle of the hub. Note that the size of the center hole is measured from the back. Every car is different. BENZ is generally 66.6MM, BMW is generally 72.6MM. If the axle hole of the rim is large, the middle hole collar must be used, otherwise the wheel will shake at high speed.
China's rim specification code is basically in line with international standards. Its nominal width and nominal diameter are expressed in inches. The coupling symbol (* or -) in the middle indicates whether the rim is a whole wheel.
Hub (g ǔ） Also called rim. In the past, single row tapered roller or ball bearing was the most widely used car hub bearing. Now three generations of hubs have been developed: the first generation is composed of double row angular contact bearings. The second generation has a flange on the outer raceway to fix the bearing, which can cover the bearing on the axle and fix it with nuts, making it easier to maintain the car. The third generation hub bearing unit adopts the bearing unit to cooperate with the anti lock brake system.
Rim (w ă Ng) It is a component for mounting tires around wheels, and it is the middle part for fixing tires and connecting tires and axles. China's rim specifications are basically in line with international standards. The rims in China are produced according to the national standard GB/T3487-2005. For example, 4.50E * 16 represents a complete rim with a nominal width of 4.5 inches and a rim code of E.
Hub is also called rim. According to the characteristics and needs of different models, the wheel hub surface treatment process will also take different ways, which can be roughly divided into two types: paint baking and electroplating.
The appearance of the wheels of ordinary models is considered less, and good heat dissipation is a basic requirement. In terms of technology, baking paint treatment is basically adopted, that is, first spraying and then electric baking. The cost is relatively economic, the color is beautiful, and the retention time is long. Even if the vehicle is scrapped, the color of the wheels remains unchanged.
The surface treatment process of many Volkswagen wheel hubs is baking varnish. Some fashionable, avant-garde and dynamic colored wheels also use paint baking technology. This kind of wheel hub has moderate price and complete specifications.