Enduro Bearings 61903 ball bearing 61903/29.5 LLB ABEC 5 17x29.5x7mm

• Bearing-No.: 61903
• Measures: 17x30x7mm // 17x29.5x7mm (inner diameter x outer diameter x width)

ABEC 5
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.

LLB
Our most popular seal type, this is a Nitrile material rubber with a steel insert. Rather than the standard 2RS type seal, we go a step further by machining a groove into the inner race where the seal can rotate with better efficiency and less rolling resistance. Rather than one thick seal lip rubbing on a blunt surface, LLB type utilizes two razor thin sealing lips riding in the groove with light contact. The outside lip keeps the water and contaminates out, while the inner seal retains the grease for smooth function and long intervals between servicing.

• 1 x Enduro Bearings 61903 bearing ABEC_5 (see item description for details)