In the past, the wheel hub bearings of cars used to use single row tapered roller or ball bearings in pairs. With the development of technology, car hub unit has been widely used in cars. The application range and amount of hub bearing unit are increasing day by day, and now it has developed to the third generation: the first generation is composed of double row angular contact bearings. The second generation has a flange on the outer raceway for fixing the bearing, which can simply sleeve the bearing onto the axle and fix it with nuts. Make the maintenance of the car easier. The third generation wheel hub bearing unit adopts the combination of bearing unit and anti lock brake system ABS. The hub unit is designed with an inner flange and an outer flange. The inner flange is fixed on the drive shaft with bolts, and the outer flange installs the whole bearing together. Worn or damaged wheel hub bearing or wheel hub unit will cause inappropriate and costly failure of your vehicle on the road, and even harm your safety.