The ABEC Rating and Tolerances
- Category: Bearings
Many skateboard bearings are marketed with an "ABEC rating" of 1, 3, 5, 7 or 9. But what do these ratings mean, and do they correspond to how well a bearing works for skateboarding?
The Annular Bearing Engineering Committee was created to set standards for bearing tolerances. ABEC sets tolerances, which are only the dimensions of the entire unit and allowable spaces between the balls and the inner ring and the outer ring (also called races). That's all!
The ABEC scale does not rate speed, durability, axial and torsional loads, torque, steel grade, ball sphericity, materials, surface finish, raceway depth, ball size, lubrication, and on and on. ABEC strictly measures tolerances. If ABEC only measures tolerances and does not rate all these other factors, can an ABEC 3 bearing actually function better than an ABEC 7? Of course it can.
Now, if ABEC just measures tolerances and gives a bearing a rating based on where it falls on the scale, what is the point of ABEC when there are so many other vital factors to consider? ABEC tolerance measurements are guidelines to follow for the manufacturing of precision bearings.
Tolerances are crucial for proper bearing function and load handling. A bearing has to have tolerances in order to rotate. The tighter or smaller the tolerance, the more accurate a bearing will spin. The reason is that the balls have less room to move on the raceway (the groove the balls roll on).
Tighter tolerances usually equal more precision and better functionality going straight down a hill or during wide turns. However, a tighter tolerance, or higher ABEC rating does not presume the bearing is faster. It only implies a bearing may function more efficiently at higher speeds. You still have to factor in axial and torsional loads, torque, material grade, ball sphericity, surface finish, raceway depth, ball size, and lubrication.
Because of these additional factors, a lower ABEC bearing may actually operate better than a higher ABEC rated bearing. This is particularly true for street and park skating.
When the ABEC scale was developed by the American Bearing Manufacturers Association, they did not create it with skateboarding in mind, nor did they account for all the abuse skateboarders give bearings.
Tolerances are important, however, the tolerances set in the ABEC scale are not necessarily the most beneficial when it comes to skateboarding, which is why ABEC tolerances do not apply for skateboard bearings. In skateboarding, tolerances need to be adjusted differently in order to handle the axial and torsional loads that skaters vigorously apply.