SBF─IR inner ring is processed by heat treatment and precision machining. The dimensional tolerance and geometric accuracy meet national standards. The  ends of the raceway surface generally have guide chamfers for installation. It is suitable for occasions where the shaft cannot be heat treated and  used directly as  raceway. The inner ring can achieve normal working clearance when  using with needle roller bearings without inner ring made in SBF.

The tolerance value of the LR inner ring is bigger than that of the IR inner ring. The end face is not ground, and the price is also low. It is often used  with the  drawn cup needle roller bearing made in SBF.