The purpose of a radial bearing is to reduce rotational friction and support loads. This is achieved by using two races to hold the balls and to spread the load through the balls. As the bearing race rotates it causes the balls to rotate. The ball provides for substantially less rolling resistance and coefficient of friction than if two flat surfaces were rotating.
Single-row, deep groove radial ball bearings are the most common bearing type, having a wide range of applications. Radial bearings are made with very high levels of precision and used in applications where rotational performance and low torque is necessary, but load is a secondary issue. Deep-groove bearings however do have higher load ratings for their size than shallow-groove ball bearings, but are also less tolerant of misalignment.
Ceramic hybrid ball bearings use ceramic balls. Ceramic balls weigh up to 40% less than steel balls, depending on size. This reduces centrifugal loading and skidding, so hybrid ceramic bearings can operate up to 50% faster than conventional bearings. This means that the outer race groove exerts less force inward against the ball as the bearing spins. This reduction in force reduces the friction and rolling resistance. The lighter ball allows the bearing to spin faster, and uses less energy to maintain its speed. Ceramic hybrid ball bearings use these ceramic balls in place of steel balls. They are constructed with steel inner and outer rings, but ceramic balls so they are known as hybrids.