Precision Classes

Share This Page

The International Organization for Standardization (ISO), German Institute for Standardization (DIN), and the ABEC; the Annular Bearing Engineering Committee of the American Bearing Manufacturers Association (ABMA) determine the most common bearing precision classes.


These standards are the precision dimensional specifications to which all bearing manufacture must conform. This allows end-users to understand how the bearings will interact with their mechanical system, enabling them to design effective mating parts.


The stack up of tolerance is a critical aspect of designing a complex mechanical system as the bearing fit within the shaft and housing is determined in part to the tolerance band. These standards and classes also provide clarity regarding the impact of the bearings on the system with dimensions such as roundness, runout, parallelism, and taper. Increased parallelism for example can positively impact running torque, and a reduced bearing runout can better balance the system.


Our team of engineers here at UNASIS can assist you in determining the precision class of bearing needed for your design, and provide the relevant empirical impact data to validate this. This validation is especially critical in contexts where the cost implications need to be justified.


UNASIS Bearings has a vast network of distributors to reach all corners of the globe. No matter where you are, you will get the best service to go along with the best bearings.

Contact Us Today

For more information, please call us today on +44 (0) 1235 527 770 or email [email protected]

First Name*


Last Name*


Email Address*








I would like to receive marketing from UNASIS via: