Needle roller assemblies according to DIN 5405-1/ISO 3030 are single or double-row units 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 roller assemblies allow for bearings with minimal radial space requirements. They are very load-bearing, suitable for high speeds, and particularly easy to assemble. With precisely shaped raceways, bearings with high roundness accuracy can be achieved. The radial clearance is influenced by the type of needle rollers as well as the shaft and housing tolerances. Needle roller assemblies require that the raceway on the shaft and in the housing is hardened and ground. Double-row needle roller assemblies are only available in specific outer diameters FW. They are marked with the suffix ZW.