Single-row angular contact ball bearings have raceways in the inner and outer ring that are offset to each other in the direction of the bearing axis. They accept axial forces in one direction only.
Under radial load, a force acting in the axial direction develops in the bearing and must be compensated by a counter-force. The bearings are therefore adjusted against a second bearing.
The contact angle α is 40° for bearings with suffix B and 20° or 30° for bearings without suffix. It is the angle between the line connecting the two contact points of ball and raceways and the radial plane, under which the load is transmitted from one raceway to the other.