The outer ring raceway of self-aligning ball bearings forms a spherical surface whose centre is common to the bearing centre. The inner ring of the bearing has two raceways. The balls, cage, and inner ring of these bearings are capable of shifting in order to compensate for a certain degree of misalignment with the outer rings. As a result, the bearing is able to align itself and compensate for shaft/housing finishing unevenness, bearing fitting error, and other sources of misalignment.
Since axial load capacity is limited, the self-aligning ball bearings are not suitable for applications with heavy axial loads.