In fact, in the late 1960s, SKF developed hbu1 (hub bearing unit 1) in response to the automotive industry's interest in pre adjusted hub bearing assembly. Today, hbu1 (hub bearing unit 1) is still the most widely used hub bearing unit in the world. As the first choice of driving wheel application in small and medium-sized vehicles in history, double row angular contact ball bearings with ring and ball sleeve are used to provide the required axial clearance. The contact angle is optimized to provide specific preload and bear specific hub load conditions.
