Also, Inner rings are a simple and quick possibility to provide a counter face for radial shaft seals without any hardening and fine machining of the shaft. The rings are simply pushed in position e.g. over a worn area. Inner rings together with radial shaft seals are a perfect compatible sealing system
When using an inner ring with sufficient width, it can be used for both functions: as seal counter face and raceway for a needle roller bearing.
Inner rings are recommended for applications where operating conditions for the seals and the counter face are difficult, particularly where solid contaminants can reach the seals or where PTFE seal materials with abrasive fillers are used.