Easton upgrades M1 mountain bike rear hubs

New bearings and sleeve offer improved durability

Easton has announced a bearing upgrade for its M1-series rear hubs. It will supposedly boost bearing durability up to ten-fold by reducing play and side loading. Easton currently uses these hubs in its EC90 XC, EA90 XC, EC70 Trail, Haven, Haven Carbon, Havoc, and EA90 XD wheelsets.

While Easton has changed the bearing size slightly, the key change is the addition of a support sleeve between the two main hub shell bearings, which will eliminate the possibility of excess preload on the inner races. 

The second modification is a new, fixed-position end cap – meaning users will no longer be able to adjust the bearing preload but won't be able to get it wrong, either, or find it working itself loose mid-ride.

New wheelsets have already been shipping with the revamped design as of mid-February, with updated-spec boxes marked with a green dot next to the item label. Current M1 hub owners will be offered a retrofit kit free of charge, which will also include new bearings. Affected hubs will be marked directly on the shell with 'M1-121', 'M1-221', or 'M1-321' labels.

Watch the video below to find out how to install an M1 bearing spacer upgrade:

Affected owners should contact wheelinfo@eastonbellsports.com to request an upgrade kit. For more information see the Easton website.

James Huang

Technical Editor, US
James started as a roadie in 1990 with his high school team but switched to dirt in 1994 and has enjoyed both ever since. Anything that comes through his hands is bound to be taken apart, and those hands still sometimes smell like fork oil even though he retired from shop life in 2007. He prefers manual over automatic, fizzy over still, and the right way over the easy way.
  • Discipline: Mountain, road, cyclocross
  • Preferred Terrain: Up in the Colorado high-country where the singletrack is still single, the dirt is still brown, and the aspens are in full bloom. Also, those perfect stretches of pavement where the road snakes across the mountainside like an artist's paintbrush.
  • Beer of Choice: Mexican Coke
  • Location: Boulder, Colorado, USA

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