2RS vs ZZ vs Open Bearings: Choosing the Right Seal
Key Takeaways
- 2RS rubber seals are the safest default for most applications — dust and moisture resistant.
- ZZ metal shields suit clean, high-speed environments where lower friction matters.
- Open bearings allow relubrication but offer no contamination protection.
Why the seal matters
The seal determines how well a bearing keeps contamination out, how much friction it produces, how fast it can run and whether it can be relubricated. Choosing the wrong seal is a common cause of premature failure.
2RS — rubber seals
2RS bearings have two synthetic rubber seals, one on each side. The bearing is lubricated for life and the seals exclude dust and moisture well. Friction is slightly higher than a shielded bearing and top speed is a little lower, but for the majority of applications 2RS is the safest default.
Best for: dusty or moist environments, washdown areas, sealed-for-life applications, and any situation where relubrication is impractical.
ZZ — metal shields
ZZ bearings have two pressed steel shields. They exclude larger particles but are not watertight, so they suit clean, dry environments. Friction is lower than rubber seals and the bearing can run faster.
Best for: clean, dry, high-speed applications such as electric motors and precision machinery.
Open — no seals
Open bearings have no seals or shields. They offer the lowest friction and highest speed, and they allow relubrication through the bearing housing. They offer no contamination protection.
Best for: clean, lubricated environments where a lubrication system is present.
Quick decision guide
- Wet, dusty or outdoors → 2RS
- Clean, dry, high speed → ZZ
- Lubricated system, maximum speed → Open
If you are unsure, 2RS is the right choice for most general-purpose applications.
Recommended Bearing Types
Related Products in Stock
Frequently Asked Questions
Is 2RS waterproof?
2RS seals are highly resistant to water and dust but are not fully waterproof for sustained immersion or pressure washing. For washdown environments they are usually sufficient; for submerged applications consult our team.
Can I relubricate a 2RS bearing?
No. 2RS bearings are sealed and lubricated for life. Attempting to relubricate them will damage the seals. If relubrication is required, choose an open bearing.
Which is faster, 2RS or ZZ?
ZZ is faster. Metal shields produce less friction than rubber seals, so ZZ bearings have a higher speed rating. 2RS trades a little speed for far better contamination protection.
Need help choosing a bearing?
Our engineers can identify the right part from a number, dimensions or a competitor reference.