Contact seal

A contact seal presses an elastic sealing lip – typically NBR, or FKM for higher temperatures – against a counterface on the inner ring under defined preload. On sealed bearings, suffixes such as RS or 2RS (both sides) denote this design; the seal washer is usually steel-reinforced and anchored in the outer ring. Contact seals reliably exclude dust, dirt and splash water and retain the grease, enabling sealed-for-life, maintenance-free bearings. The trade-off is lip friction, which raises frictional torque and operating temperature and lowers the permissible speed compared with shields or open bearings. Low-friction contact variants offer a compromise.