What Is a 608 bearing? 608 Bearing The most common standardized ball bearing size is the 608 series. The 608 series is the original standard ball bearing. In the 608 series, the ball bearing typically consists of optional closures, inner race, outer race, balls, and ball retainer. It is characterized by an 8mm inner diameter (the bore of the ball bearings), a 22mm outer diameter, and a width of 7mm. Most of these ball bearings are manufactured to reflect an ABEC rating which is the industry standard to measure the dimensional and manufacturing tolerances of ball bearings.
The ABEC rating is graded in five tiers of 1, 3, 5, 7, and 9 ratings, where the higher the rating, the tighter the tolerances of the bearing. Ball bearings that have a high ABEC system rating are used for high precision applications such as the aerospace industry or surgical equipment, and lower ABEC graded ball bearings are used for more everyday bearing applications. ABEC ratings also reflect the relative prices of ball bearings; the higher the grading, the more expensive the ball bearings. 608 bearings are used in a wide variety of applications including skates and skateboards, electric motors, home appliances, and much more. The speed of the ball bearing has no relation to the ABEC rating. Speed of the ball bearing has a direct relation to lubrication, materials and quality.