Single row angular contact ball bearings are self-retaining units with solid inner and outer rings and ball and cage assemblies with polyamide, sheet steel or brass cages. The raceways of the inner and outer rings are offset in relation to each other in the direction of the bearing axis. The bearings are available in open and sealed versions. Their self-alignment capacity is very small. X-life Many sizes of angular contact ball bearings are supplied in X-life design. These bearings are indicated in the dimension tables. Bearings of X-life quality have an improved raceway geometry as well as optimised surfaces. This gives a significant increase in the fatigue limit load of the bearings. In calculation of the expanded adjusted rating life, values up to 50% higher are achieved. In certain applications, a smaller design of bearing arrangement can therefore be used if necessary.