Needle bearings according to DIN 5405-1/ISO 3030 are single or double-row assemblies consisting of cages and needle rollers. The single-row version is based on DIN 5405-1. Since their radial height corresponds only to the diameter of the needle rollers, needle bearings allow for the smallest radial installation space. They are very load-bearing, suitable for high speeds, and particularly easy to assemble. With precisely shaped raceways, bearings achieve high roundness accuracy. The radial clearance can be influenced by the type of needle rollers as well as the tolerances of the shaft and housing. Needle bearings require that the raceway on the shaft and in the housing is hardened and ground. Double-row needle bearings are only available in certain outer diameters (FW) and are marked with the suffix ZW.