Car wheel hub bearings in the past is the largest single-row tapered roller or ball bearings. As technology has evolved, cars have used car hub units extensively. The use of hub bearing units and the growing use of the scope, and now has developed to the third generation: the first generation is composed of double row angular contact bearings. The second generation on the outer raceway has a flange for the bearing fixed, you can simply set the bearing sleeve to the axle nut. Make car maintenance easy. The third generation of hub bearing unit is the use of bearing units and anti-lock brake system ABS match. The hub unit is designed with an inner flange and an outer flange bolted to the drive shaft, with the outer flange mounting the entire bearing together. Worn or damaged hub bearing or hub units can cause undesirable and costly failure of your vehicle while traveling, and can even cause injury to your safety.