Enduro Bearings MR 215321 ???? MR 215321 LLU ABEC 3 MAX 21.5x31x7mm

• Bearing-No.: MR 215321
• Measures: 21.5x31x7mm (inner diameter x outer diameter x width)

LLU
Similar to the LLB type seal, LLU is a full contact, dual lip seal riding in a groove on the inner race. With more sealing pressure, these are ideal for pivots or headsets that continually come in contact with dirt, sweat, and dust. The increased seal pressure and 2 lips help retain the 90% grease fill we use on these bearings to better displace any moisture and continually lubricate the balls and races.

ABEC 3
ABEC ratings (Annular Bearing Engineer’s Committee) are standards to which each bearing must pass many tests in order to meet the scheduled requirements including noise testing at high RPM, extremely tight tolerances for the internal diameter, outer diameter, roundness of ball, trueness of races, and surface finish for all of the above. Some aspects of ABEC ratings are important for bicycle bearings, but not all. In fact a high ABEC rated number for a bearing does not necessarily mean a high performance, long lasting bearing for your bicycle. For instance, you can have a high ABEC rated bearing that has a race groove only half as deep as ours because this feature is not covered by ABEC ratings. Since the groove would be shallower, there is less surface for the ball to roll on, and easier to pass the noise test. (Less surface contact = lower noise). However, the shallow groove of this bearing can yield less than half the support of our deeper groove design, and can be only half as strong; lasts half as long and becomes rough much sooner. Our deep groove ABEC 3 and ABEC 5 bearings offer the deepest grooves possible in every size, and are more difficult to pass the test due to the improved architecture of our bearings.

• 1 x Enduro Bearings MR 215321 bearing MR_215321_LLU ABEC_3 MAX 21.5x31x7mm (see item description for details)