Angular contact ball bearings are classified as single row, radial ball bearings. However, many refer to them incorrectly as thrust bearings because they are designed to carry a heavier axial load. Unlike other radial ball bearings, the contact points through the angular contact bearing are measured in terms of how far they deviate from the normal pure radial load (at a 90° angle to the shaft). Angular contact bearings are designed to operate with an internal contact angle of 15 °, 30° or 40° from the standard 90° angle to the shaft. Popular designations for the various contact angles are as follows:
Popular Designation for Angular Contact Bearings
15° angle of contact – C
40° angle of contact – D
30° angle of contact – No Designation
These bearings are designed for the balls to ride high on the edge of one of the raceways: the raceway on the opposite side of the outer ring is much shorter to accommodate assembly. If the angular contact bearing is installed facing the wrong direction, it will separate and result in a catastrophic premature bearing failure.