• Hub knowledge
  • Tire knowledge
  • Refit knowledge
Classification of wheel hub

Classification of wheels by material: steel wheel, aluminum alloy wheel

Aluminum alloy wheels have the following advantages over steel wheels:

1、1、More energy-saving
Aluminum alloy wheel has the advantages of light weight, high manufacturing precision, small deformation and small inertia resistance in the high speed rotation, which is beneficial to improve the straight driving performance of the car, reduce the tire rolling resistance, and reduce the fuel consumption.

2、Safer
The heat conduction coefficient of aluminum alloy is three times of that of steel, and the heat dissipation effect is very good, thus the braking performance is enhanced, the service life of tire and brake disc is prolonged, and the safe driving of automobile is effectively guaranteed.

3、More comfortable
The automobile with alloy wheels generally adopts flat tires with better cushioning and shock absorbing performance than ordinary tires, which greatly improves the comfort of automobiles on uneven roads or when running at high speed.

Because of its many advantages, the aluminum alloy wheel has gradually replaced the steel wheel, so far, the application ratio of the aluminum alloy wheel in the car has reached more than 70%.



Classification by production process

Aluminum alloy wheel is currently used in the main production processes: forging, hot die forging, spinning, casting.

Comparison of manufacturing cost :Forging >Hot forging>Spinning>Casting

Comparison of quality:Forging >Hot forging>Spinning>Casting

Forging wheel hub and hot mold forging can not be popularized because of the high equipment cost, high mold cost, low yield and expensive price. At present, they are mainly used in racing, supercar, and the refitting of high-class sports car.

Although the cost of spinning wheel hub equipment is high, but its mold can be universal, high yield, and the quality can basically achieve the advantages of forging wheel hub and hot mold forging wheel hub. Spinning wheels are gradually be promoted. At present, many main engine factories in Japan have used spinning wheel hub to replace the original low-pressure wheel hub.

Casting wheel hub can be divided into low-pressure casting wheel hub and gravity casting wheel hub. Although the technology of both is obsolete, they have been used to this day because of their low cost.

Comparison of manufacturing costs: low-pressure casting> gravity casting

Quality comparison: low-pressure casting> gravity casting

In low pressure casting, the pressure, temperature and cooling curve of aluminum-water in mold cavity can be controlled better, and the casting quality and casting stability are also better. It is suitable for mass production. At present, most of the main engine factories at home and abroad use low-pressure casting wheels.

Gravity casting is widely used in small batch production because of its low mould cost and short stable production time. At present, the gravity casting wheel hub is used in most of the aftermarket refitted wheel hub at home and abroad.

Wheel structure diagram
Terminology about wheel

1. Wheel size: in the case of 18x8.0, 18 refers to a hub with a diameter of 18 inches and a rim width of 8. 0 inches. The diameters and widths here refer to the diameters and widths of the locations where the tyres are installed;

2.PCD value: the diameter of the circle formed by the center of the hub bolt hole. In the case of 5x120, 5 means the number of bolt holes is 5, and 120 means the diameter of the circle in which the bolt hole center is located is 120mm.

3.Center Bore (CB) to ensure that the hub can be installed on the axle, in the case of CB73.1, refers to the diameter of the hub center hole is 73.1mm. If the center hole is smaller than the diameter of the axle, the hub can not be installed on the car. If the center hole is larger than the diameter of the axle, it can be solved by the bushing ring.

4.Geometric centerline: the centerline centered around the rim, which is the most important reference data in the hub. You must refer to this value, including the calculation of the Offset value, the distance between X, and so on.

5.Offset ET: the distance between the hub mounting surface and the geometric centerline. In the case of the ET40, the distance from the hub mounting surface to the geometric centerline is 40 mm. Positive offset if the hub mounting surface is outside the geometric centerline, otherwise negative offset. ET can be understood as the location of the hub relative to the inside and outside of the car. The smaller the et value, the more the hub will protrude in accordance with the vehicle. If the ET is too large, it will cause the tire to rub on the car body, or the spoke will hit the brake. If the ET value is too small, it will cause the hub to protrude out of the eyebrow, or the tire to rub the outer eyebrow.

6.X distance: the maximum distance between the drop surface in the hub and the geometric center line. It is a basis for determining whether hub disc surfaces and calipers will rub or touch each other.

7.There are three kinds of wheel hub surface technology

Painting. That's paint. According to the different paint and painting process, can be divided into silver, black, matte black, gun gray, bright silver, bright black, and so on. It is also the lowest price of the three.

Painting the car surface / side. That is, after painting on the wheel disc or wheel flange part of the processing, spraying a protective transparent paint on the surface. The price is a little higher than the painting.

Electroplating is divided into water electroplating and vacuum electroplating. The color of vacuum plating is more diverse, more good-looking, but the warranty time is generally about one year. Water plating have only a single mirror color, but the shelf life can be up to three years.