MR 21531 ABEC-3 Bearing

The MR 21531 LLB is an ABEC-3 radial bearing designed with a 21.5mm x 31mm x 7mm profile and C3 clearance. Engineered for durability against daily abuse and the elements, it features deep-groove races to accommodate the largest balls possible for maximum performance.

Technical Construction: Built with grade 10 balls and 90% fill of high-pressure waterproof grease. The design includes dual-lip, light-contact labyrinth (LLB) seals that ride in a micro-groove to provide superior protection against contaminants.

Specialized Fitment: This specific size is commonly utilized as a front hub bearing for older WTB 20mm hubs and has also been used for Isis bottom brackets.

Enduro Engineering: Part of the Enduro line, these bearings are manufactured with deep-groove races and high-carbon chromium steel to ensure a robust interface for high-load applications.