Needle roller bearings according to DIN 5405-1/ISO 3030 are single or double-row units consisting of cages and needle rollers. The single-row design is based on DIN 5405-1. Since their radial height corresponds only to the diameter of the needle rollers, needle roller 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 play can be influenced by the type of needle rollers as well as the shaft and housing tolerances. Needle roller bearings require that the raceway on the shaft and in the housing is hardened and ground. Double-row needle roller bearings are only available in certain outer diameters and are marked with the suffix ZW.