Bearings Bearings are basic and essential components of all machinery. There are dozens of bearing types designed for optimum performance under different speeds, loads, environments, etc. Rotational bearings, the most common type, allow one component to rotate relative to another. These bearings must resist radial loads, which are forces perpendicular to the shaft’s axis, and thrust loads, which are forces parallel to the shaft's axis. Thrust bearings are a subset of rotational bearings which are designed to take axial (thrust) loads only. Linear bearings, the other major class of bearings, are designed to optimize travel along the length of a shaft. All bearings must offer as little frictional resistance to movement as possible to minimize drive power loss.