Exclusive to Enduro Bearings, our XD-15 Ceramic-Hybrid bearings feature cryogenically treated nitrogen steel races paired with Grade 3 Silicon Nitride ceramic balls through a proprietary manufacturing process. The deep-groove raceways maximize ball size, enhancing contact area for superior performance and durability. Filled with 90% Kluber NBU52 grease, these bearings improve with use while resisting washout—the specialized formula adheres to the ceramic balls and continuously recirculates into the ball path for optimal lubrication.

Unlike conventional options, these bearings uniquely improve with operation—the ceramic balls progressively polish the races during use, creating increasingly refined surfaces. While competing ceramic-hybrid bearings may offer comparable initial performance advantages, Enduro XD-15 bearings distinguish themselves by actually enhancing speed and smoothness over time. This progressive performance improvement stands in stark contrast to alternative ceramic-hybrid bearings, which invariably experience degradation and reduced efficiency with continued use.

This bearing serves primarily as a direct replacement component for Shimano external cup bottom brackets when utilized with the Shimano plastic bearing insert. For applications where eliminating the plastic insert is preferred, the MR 2437 bearing represents the appropriate alternative specification for optimal installation and performance.