Bearing seals and shields: 2RS, 2Z, ZZ, DDU, LLU and other suffixes

Is 2RS a universal bearing suffix?

No. Distributors commonly use 2RS to mean a bearing sealed on both sides, but major manufacturers publish their own codes and designs. NSK uses DDU for two contact seals, SKF uses 2RSH or 2RS1 depending on the size and design, NTN uses LLU, and Schaeffler/FAG uses codes including 2RSR and 2HRS.

Those codes describe broad closure classes, not automatic cross-brand equivalence. Lip geometry, contact mode, seal material, grease fill, friction, speed capability and temperature limits can differ. Keep the literal maker designation when identifying or ordering a bearing.

Open, shielded and sealed are different constructions

An open bearing has no closure suffix in the manufacturer systems reviewed here. A metal shield is a non-contact closure, commonly NSK or NTN ZZ and SKF or current FAG 2Z. It is not the same construction as a rubber non-contact seal.

Rubber seals can be contact or non-contact designs. NSK VV, SKF 2RZ, NTN LLB and FAG 2BRS are manufacturer examples of non-contact rubber sealing. Contact-seal examples include NSK DDU, SKF 2RSH or 2RS1, NTN LLU and FAG 2RSR or 2HRS. Exact availability depends on the bearing size and product range.

Can a shielded bearing replace a sealed bearing?

Matching boundary dimensions do not answer that question. Closure choice affects contaminant exclusion, lubricant retention, friction and speed. Check the original complete designation, machine environment and current manufacturer data rather than replacing one closure class with another solely because both bearings fit the same seat.

How should suffix tables be used?

Use the table below as a manufacturer-designation guide, not an equivalence chart. A row says how each manufacturer names a broad construction in the cited literature. It does not say the products are functionally identical.