Rolling bearings support and guide with minimal friction, rotating or oscillating machine elements, such as shafts, axles or wheels, and transfer loads between machine components. According to the shape of the rolling elements, the two basic types of balling is ball bearing and roller bearing, balls and rollers are different in how they make contact with the raceways. 

Balls make point contact with the ring raceways. With increasing load acting on the bearing, the contact point becomes an elliptical area. The small contact area provides how rolling friction, which enables ball bearings to accommodate high speeds but also limits their load-carrying capacity.

Rollers make line contact with the ring raceways. With increasing load acting on the bearing, the contact line becomes somewhat rectangular in shape. Due to the larger contact area and the consequently higher friction, a roller bearing can accommodate heavier, but lower speeds, than a same-sized ball bearing.

Additionally, a typical rolling bearing consists of an inner ring, an outer ring, balls or rollers as rolling elements and a cage.