Riders and mechanics rebuilding 24 mm external or press-fit bottom brackets.
The Enduro MR 2437 is a 24 x 37 x 7 mm radial bearing, and its most common job is replacing the bearings in Shimano-style external cup bottom brackets that run a 24 mm spindle. It is also used in BB86, BB92 and adaptor setups built around the same bearing.
It is an ABEC-5 bearing with 52100 high-carbon chromium steel races, Grade 5 balls and C3 clearance, filled 90% with Mobil XHP 222 waterproof grease. The clever part is the seal pairing: a grey LLU seal faces outward to fight water and dirt, while a lighter black LLB seal faces inward so the bearing spins freely.
If your bottom bracket feels gritty or has play but the cups are still in good shape, a pair of these brings it back to life for much less than a new unit.
Common BB size
24 x 37 x 7 mm, the standard 24 mm spindle bearing.
ABEC-5
Grade 5 balls and C3 clearance for a smooth spin.
Smart sealing
Grey LLU outside, black LLB inside.
Waterproof grease
90% fill of Mobil XHP 222.
Bearing
In the box
LLU/LLB seal pairing
A heavier-contact grey LLU seal faces the weather while a lighter black LLB seal faces inward, keeping dirt out without adding much drag.
ABEC-5 precision
Tighter tolerances and Grade 5 balls for a smooth-spinning bottom bracket.
Great for
Maybe not for
Sold as a single bearing. A bottom bracket takes two, so order a pair. Fit with the grey LLU seal facing outward.
Seal orientation matters
Fit the bearing with the grey LLU seal facing out towards the weather and the black LLB seal facing the inside of the frame. Use a proper bottom bracket bearing press and support the outer race so you do not damage the new bearing.
Bearings made for bikes.
Enduro Bearings makes cartridge bearings designed specifically for bicycles, from hubs and bottom brackets to headsets and suspension pivots.
The range covers high-carbon chromium steel, 440C stainless steel and ceramic-hybrid bearings, all built with deep-groove races and dual-lip labyrinth seals to keep grease in and grime out.
