Riders replacing a worn MR137 (37 x 46.85 x 7 mm, 45/45) headset bearing.
The Enduro ACB 4545 137 SS is an angular contact headset bearing sized 37 x 46.85 x 7 mm with 45 x 45 degree chamfers, known across the industry as an MR137. It suits integrated headsets and frames built around this bearing.
Both the balls and races are 440C stainless steel, the hardest of the standard 440-series stainless alloys, so it resists the corrosion that ruins headsets exposed to rain, sweat and spilled sports drink. LLB-type seals and a 90% fill of Almagard 3752 grease add more protection.
Enduro makes a point that its stainless headset bearings are the same ones found in many popular headset brands. When your steering starts to feel notchy or rough, this is a direct swap for a worn MR137.
MR137 size
37 x 46.85 x 7 mm with 45 x 45 degree angles.
440C stainless
Balls and races resist corrosion from sweat and rain.
Angular contact
Spreads steering loads evenly across all balls.
Sealed and greased
LLB seals with 90% Almagard 3752 fill.
Bearing
In the box
440C stainless
The hardest and most wear-resistant of the standard 440-series stainless alloys, chosen for corrosion resistance in wet or sweaty conditions.
Angular contact
All balls share the steering load evenly, which suits the combined radial and axial forces in a headset.
Great for
Maybe not for
Measure your old bearing before ordering: this one is 37 mm inside, 46.85 mm outside and 7 mm tall, with 45 degree chamfers on both sides. Sold individually.
Match the old bearing exactly
Headset bearings look alike but differ by fractions of a millimetre and by angle. Check the markings on your old bearing or measure it, and bring it in if you are unsure. Clean the frame seats and add a thin layer of grease before fitting.
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.
