IR series inner rings are used as parallel partners for needle-roller bearings or sealing rings. Because of their standardization and economic availability, they are also popularly used as spacer rings. They are machined from hardened roller bearing steel and have precision machined raceways.
LR series bearing rings are ground but the front faces are only turned and the edges are blunted and have more tolerances in the width B overall.
Suffixes
Lubrication hole, twist-free grinding, bearing clearance