Almost all ball bearings have an ABEC rating, classifying it from other bearings, and often influencing price. So what does this rating mean, and just how important is it?

The ABEC Scale

The ABEC scale was developed by the Annular Bearing Engineering Committee to standardize measurements of the tolerance levels of a ball bearing. These measurements include diameter and width of the raceways, shape of the bearing, and surface smoothness. This is extremely useful for precision bearings that have specific performance requirements for their application. With a standardized scale, consumers have security in knowing the precise specifications of a given ball bearing.

The scale has five categories of tolerance: 1, 3, 5, 7, and 9. Higher ratings mean the bearing has greater efficiency, precision, and speed capabilities. This means the bearing has more reliable performance at high speeds, not necessarily that it can spin faster. The ABEC scale is extremely precise; each class differs only by a few microns of acceptable deviation in tolerance. Any bearing below ABEC 1 requirements is not classified as a precision bearing. High rated bearings are typically used for applications such as aircraft instruments, robotics, and surgical equipment, as well as other industries with high speed and low friction requirements. Lower rated bearings are more widely used in applications such as skateboards, industrial machinery, agriculture, and vehicles.

The ABEC scale originated in the United States; there are other similar scales used in other nations as well. The DIN 620 originated in Germany and is commonly used throughout Europe. The International Organization for Standardization also has a comparable bearing scale, called ISO 492, however it is not as commonly used among high precision bearings.

Other Factors of Bearing Performance

There are a multitude of factors that the ABEC scale does not take into account, such as load capabilities, component materials, level of polishing, type of lubricant, Rockwell hardness, and noise and vibration levels. These factors of course have a large impact on bearing performance and suitable applications. Therefore, an ABEC rating does not indicate overall quality of the bearing, as an ABEC 3 bearing could have greater performance than an ABEC 7, if it has superior engineering. For this reason, some industries may use their own bearing quality scale, such as the skate rating for skateboard bearings. As these types of bearings do not require high ABEC ratings, a skate rating takes into account other important factors such as durability and materials. This modified scale provides consumers with a more applicable standard for skateboard bearings than an ABEC rating would.

Most ball bearing manufacturers should offer multiple quality rating tools to provide complete information about bearing performance. At MRO Supply, detailed bearing descriptions are always available, as well as bearing experts to answer questions about which bearing is suitable for a given application.