Bearing FAQs – ABEC, bearing lubricants, flanges, and more

A ruby-tipped probe from a Coordinate Measuring Machine (CMM) inside the SRF Test Lab at Jefferson Lab in Newport News, Va., on Wednesday, Feb. 8, 2023. (Photo by Aileen Devlin | Jefferson Lab)

We know when you’re ordering bearings, you need as much information as possible. That’s why we’ve collected the answers to our most frequently asked bearing questions in one convenient place. If you have a different question about our business, bearings, or our clean room services like repackaging and relubrication, use our contact form to reach out or email us at We’re here to help. 

Can bearings be refurbished? 

Yes, but refurbishing bearings isn’t necessarily a practical choice. 

It’s not always economical to refurbish small bearings. However, refurbishing larger-size bearings (6-inch or greater bore) can be cost-effective. 

Bearings such as slewing rings, cylindrical roller bearings, and spherical roller bearings can be ideal candidates for refurbishing. However, beyond the bearings’ accumulated wear, many other factors affect the decision to refurbish. These factors include maintenance cycles, lubrication, MTBF (mean time between failures), and environmental considerations.  

Learn more about bearing maintenance and repair. 

What are ABEC ratings? 

The ABEC scale is an industry-accepted standard for the tolerances of a ball bearing. The Annular Bearing Engineering Committee (ABEC) of the American Bearing Manufacturers Association (ABMA) developed the ABEC scale. The scale contains five classes, from widest tolerances to tightest: 1, 3, 5, 7, and 9. 

Higher ABEC classes provide better precision, efficiency, and greater speed capabilities, but don’t necessarily mean the bearing can spin faster. Additionally, ABEC ratings do not specify many other critical factors, such as the smoothness of the rolling contact surfaces, ball precision, and material quality. 

Does a higher ABEC rating mean a quieter bearing? 

There may be a loose correlation between ABEC precision ratings and noise, but higher ABEC ratings do not always mean quieter bearings. ABEC ratings do not specify many other critical factors, such as the smoothness of the rolling contact surfaces, ball precision, and material quality, all of which can affect noise. 

Another major factor in bearings’ noise performance is lubricant type. For the quietest running, it’s crucial to select a quiet grease. Handling, installation and correct preloading also ensure the quietest possible operation. 

How do I select the right bearing for my application? 

Alpine strongly suggests that you contact one of our bearing application engineers when you’re selecting your design specifications. Alpine’s experienced sales and engineering staff will help with your design and selection process, maximizing performance and ensuring your success.? 

Are Alpine Bearing’s rolling element bearings RoHS compliant? 

Yes, all Alpine Bearing’s rolling element bearings are RoHS (Restriction of Hazardous Substances Directive) compliant. Contact us if you require proof of RoHS certification. 

The RoHS directive was adopted by the European Union (EU) in July 2006. People often call RoHS the “lead-free directive,” but the directive restricts the use of the following six substances: 

  • Lead (Pb) 
  • Mercury (Hg) 
  • Cadmium (Cd) 
  • Hexavalent chromium (Cr6+) 
  • Polybrominated biphenyls (PBB) 
  • Polybrominated diphenyl ether (PBDE) 

Because Alpine is in the United States, we are not limited to selling RoHS-compliant bearings. Though all our rolling element bearings are RoHS-compliant, we also offer a small number of plain bearings which include lead as part of their functional design (lubrication). We clearly identify these bearings in their material makeup. 

What are ABEC and ISO precision level equivalences?

ABEC precision levels ABEC-1, ABEC-3, ABEC-5, ABEC-7, and ABEC-9 are equivalent to ISO precision levels P0, P6, P5, P4, and P2 respectively.

ABEC precision levels  ISO precision levels 
ABEC-1  P0 
ABEC-3  P6 
ABEC-5  P5 
ABEC-7  P4 
ABEC-9  P2 

Learn more about ISO and other standards for bearings. 

What is the shelf life of a bearing? 

The most important factor for determining a properly stored bearing’s shelf life is lubrication.?Greases and oils?have expiration dates, so a bearing’s shelf life depends on when its lubrication expires. Otherwise, provided the bearing is stored properly, the potential effects of contamination and oxidation will be minimal and should not significantly affect its shelf life. Properly storing bearings typically means keeping them in their original factory packaging, or having them professionally repackaged. 

What bearing grease or oil is the best? 

It’s all relative. Selecting the best bearing lubricant, whether grease or oil, depends on the application and conditions. With a wide variety of greases and oils available, there’s a solution for most applications. 

However, there is no perfect grease, whether natural, synthetic, micro-filtered or otherwise. Every type of grease or oil features different performance characteristics. For example, high-temperature greases typically cannot handle high loads well. Additionally, quiet greases may break down at high temperatures. There is no single best grease or oil for bearings. The best lubricant varies based on which properties are most important for the given application. 

If you’re unsure which bearing lubricant will best fit your specifications, contact Alpine Bearing’s bearing application engineers. We can help you choose the ideal oil or grease for your needs. 

What are flanged bearings? 

Many ball bearings have flanges as a configuration option. The flange is designed to aid in mounting and positioning, especially for bearings on external housings.?Flanges are most common on miniature and instrument bearings, but are also available on other ball bearing types.

What’s the difference between bearing seals versus bearing shields? 

Seals and shields both keep contaminants out of a bearing. From least to most effective, the enclosures we offer are as follows: 

  • Metal shields 
  • Rubber non-contact seals 
  • Teflon non-contact seals 
  • Rubber contact seals 

Not surprisingly, as sealing performance increases, the torque required to turn the bearing will also increase due to increased friction caused by the seal/shield. 

To determine the best shield or seal choice, it’s important to know the bearing application’s condition and life requirements. Different operating environments may require different types of seals or shields. 

Do you have more bearing questions? 

Alpine is committed to providing the best bearings and the best information for our customers. We’ll continue to post articles explaining the technical aspects of bearings and their applications. If you have questions or if you’d like us to expound on a particular subject, please talk to one of our sales engineers. 

And, if you’re wondering about bearing terminology, don’t miss The Bearing Glossary to End All Bearing Glossaries. 

Photo by Aileen Devlin | Jefferson Lab