Tolerances control the dimensional accuracy of a bearing.

For exact tolerance limits, please view our TOLERANCE TABLES
To see what measurements are checked, see BEARING TOLERANCES EXPLAINED

ISO bearing tolerances start at P0 and then move upwards to precision grades P6, P5 and then P4. ISO tolerances are measured in thousandths of a millimetre (or microns). AFBMA (ABEC) bearing tolerances are also commonly used and these are measured in ten-thousandths of an inch with grades Abec1, Abec3, Abec5 and Abec7. There are slightly different Abec tolerance grades for instrument bearings (Abec1P, Abec3P, Abec5P, Abec7P) and for thin-section bearings (Abec5T, Abec7T).

Assuming that the shaft and housing are manufactured to the same tolerances as the bearing, tighter bearing tolerances will improve mating between shaft/housing and bearing, noise/vibration levels and starting/running torque.

Our determination to remain specialised gives us a high level of product knowledge, providing bearing and lubrication solutions to existing or potential customers, whether individuals or large corporations. We don’t just sell bearings, we help to solve your problems. - Chris Johnson, managing director of SMB Bearings.