I replaced the bearings in my Tune Kong rear hub back in July (replaced the 2 in the hub shell and the 2 inner/outer freehub bearings). All 4 were INA-FAG bearings, installed with presses/Loctite bearing fit and were all seated correctly and perfectly smooth. Now 3months later the rear axle felt notchy, so stripped down the hub to find the inner freehub bearing is notchy, and the other 3 bearings are still smooth.

I’m a bit puzzled by why just this single bearing is shot – the hub/freehub was still greased ie not full of crud/water when pulled apart, the bearing was installed without touching the inner race and aligned correctly, no spacers etc were missing.

Any ideas?