IKO Inner Rings are heat-treated and finished bygrinding to a high degree of accuracy. In the case of needle roller bearings, normally, the shafts are heattreated and finished by grinding, and used as the raceway surfaces. However, when it is impossible to make shaft surfaces according to the specified surface hardness or surface roughness, inner rings are used. Inner rings include those for Shell Type Needle Roller Bearings and those for general use and are available in a variety of dimensions. When shafts move axially or seals are used adjacent to bearings, wide inner rings can be selected. Inner rings can also be used economically as bushings without requiring any additional machining.