MR2437 LLB Enduro Sealed Radial Bike Bearing Abec 3 - 24x37x7mm

ABEC-3 Radial Bottom Bracket Bearing featuring Black-Oxide treated 52100 High-Carbon Chromium alloy races paired with grade 10 Balls with 90% fill, Mobil XHP 222 high-pressure, water-proof grease.

The most common use for this bearing is as a direct replacement bearing for Shimano-type external cup BBs and cranksets with 24mm spindles.

The Enduro line of bearings are available in high-carbon chromium steel, 440C stainless steel, ceramic-hybrid and XD-15 with ceramic or stainless balls. Our bearings are always engineered with deepest groove races possible to accommodate the largest balls and feature dual-lip seals that ride in a micro-groove creating a full labyrinth to provide superior protection against the elements.

Static load - 726lbf / 3.22kN
Weight - 31g

LLB Seals are Enduros most popular light contact seal. LLB seals are comprised of Nitrile material rubber with a steel insert and ideally suited for constantly spinning bottom bracket and hub bearings. Rather than one thick 2RS seal lip rubbing on a blunt surface, LLB type utilises two razor thin sealing lips riding in the bearing race groove. The outer lip keeps the water and contaminants out, while the inner lip retains grease for smooth function and longer intervals between servicing.

ABEC Ratings (Annular Bearing Engineers Committee) are manufacturing and testing standards that each bearing must pass. These include noise testing at high RPM, precisely defined tolerances for inside and outside bearing diameters, roundness of ball, trueness of races, and the surface finish for all of the above. ABEC ratings are numbered 1 thru 9, odd numbers only, with 9 being the best possible rating. A bearing with a 7 or 9 rating is very difficult and expensive to manufacture, might be perfect for a 40,000 rpm dental handpiece, but is overkill for the slow rotational speeds of bicycle cranks and wheels.

Some aspects of ABEC ratings are important for bicycle bearings, but not all. In fact, a high ABEC rating does not mean the bearing spins with less drag, nor does it necessarily equate to high performance, long lasting bearings. ABEC standards do not account for critical bicycle performance influencers such as load handling capabilities, ball grade and precision, Rockwell hardness, bearing seal quality or lubrication specification. This can lead to confusion in the bicycle marketplace.

For instance, a high-ABEC rated bearing that includes a very shallow race groove will run very quietly, but will also be more susceptible to the axial loads typical to cycling and as a result may be subject to premature wear and potential failure. Conversely, Enduros ABEC 3 and ABEC 5 bearings – designed specifically for bicycle application – offer the deepest grooves and largest balls possible in every size to increase bearing strength and durability. Due to this increased ball size and groove depth, our bearings require tighter manufacturing tolerances combined with exacting finish and assembly protocols to meet ABEC standards, resulting in greater precision overall.

52100 Chromium Steel Balls riding inside deep-grooved bearing races are whats inside Enduros ABEC 3 (grade 25) and ABEC 5 (grade 10) bearing assemblies. 52100 chromium steel balls riding inside deep-grooved bearing races. 52100 chromium steel can be manufactured to very high levels of precision, and when combined with double lip seals and filled with high performance grease, is the basis of an excellent bearing. Bearings made from 52100 chromium steel are found on many of the highest priced bikes from the most respected brands in the world. They offer premium performance and dependability at a very affordable price.