2RS Bearings: Rubber Contact Seals on Both Sides

What the seal actually does

The lip is moulded with a slight interference against the inner ring shoulder, so it stays in contact even when the shaft deflects. That contact is what keeps grease in and water out: there is no path around the lip. The same contact is also a continuous brake. On a 6205 running at 3,000 rpm, a pair of 2RS lips adds measurable drag and raises the running temperature by 5–15 °C compared with a shielded bearing — which then shortens grease life, because grease life halves for every 15 °C rise.

Where 2RS is the right call

Specify 2RS when the bearing is greased for life and the environment is the dominant risk rather than speed.

• Conveyor, fan and pump positions with dust, fibre or moisture in the air.
• Outdoor or unheated installations where condensation forms during shutdown.
• Food, packaging and agricultural machinery that is washed down between shifts.
• Any position where a grease nipple is impossible and the bearing must last its full design life on one fill.

Where 2RS goes wrong

Most 2RS failures we are asked to diagnose are not contamination failures but heat failures caused by the seal itself.

• Above roughly 70% of the open speed rating, lip temperature climbs faster than the grease can tolerate and the lip hardens or burns.
• Above 120 °C the NBR compound hardens, loses elasticity and stops sealing — the grease then escapes and the bearing runs dry.
• In continuous immersion or pressure washing the lip cannot hold; water migrates past it and emulsifies the grease.
• If the maintenance plan requires relubrication, 2RS is simply the wrong bearing — the seal has to be destroyed to reach the raceway.