Levo Gen 2 2019 Levo rear hub bearings

[Paramaniac]

I had to replace the rear hub bearings (6903-LU). I suspect the reason they went was because they were over tightened (to much pre-load). What I cannot determine is how much do the axle/shaft nuts have to be tightened. Asked the local shops and getting conflicting info from very tight to finger tight and then tightening the lock nut. they need to be tight enough so that the inner race will not spin on the shaft but not so much that it will cause the bearing to fail.

I come from an automotive background and usually ball bearings are not pre-loaded unlike wheel bearings are pre-load. The thing that surprises me about the way it is done on the levo, is that there is no spacer between the inner races of the bearings thus if the axle/shaft nuts are over tightened it puts to much lateral force on the bearing which will cause it to fail prematurely and also makes it feel gritty and if left to loose you run the risk of the inner races spinning around the shaft and damaging it, not to mention that the wheel will feel loose/wobble side-to-side. This design seams to be unique to this hub cause I've seen other hubs with sealed bearings that have a build in spacer/stops on the axle/shaft. BTW there is a spacer on the cassette free wheel hub which is how it should be so that the inner races can be tightened without any concern about putting undue lateral stress on the bearing.

Does anyone know how to set the pre-load on the rear hub (the 6903) bearings? What is the correct procedure?

Thanks.

 

[congerball]

Good question...also..if you don’t mind me asking, what does the black nut do? and what does the silver nut do on the non drive side?

 

[Paramaniac]

Good question...also..if you don’t mind me asking, what does the black nut do? and what does the silver nut do on the non drive side?

The black nut is the one you set the preload and the silver is the lock nut that keeps it at that set position.

 

[Mikerb]

Cartridge bearings unlike cone bearings do not need pre load. All that is required with the nut on the non drive side is to remove any lateral movement of the axle. I gently tighten the nut until I just start to feel some resistance on the rotation of the axle as felt by hand...then back the nut off a quarter turn. The outer nut then just locks against the inner nut to maintain that adjustment. On the drive side, the single nut is reverse thread. I tighten that finger tight plus a quarter turn.