XLCPro hub bearings

[vRSG60]

My Haibike has an XLCPro rear hub. The bearings need replacing but looking at the hub there’s no spacer between the bearings. I’ve not got new bearings yet but the old ones lock up when the nuts are gradually tightened on the axle. Surely there should be something to tighten against!
By the way they are sealed bearings.

 

[PedalUma]

My Haibike has an XLCPro rear hub. The bearings need replacing but looking at the hub there’s no spacer between the bearings. I’ve not got new bearings yet but the old ones lock up when the nuts are gradually tightened on the axle. Surely there should be something to tighten against!
By the way they are sealed bearings.

Can you attach some photos? That would help a lot.

 

[vRSG60]

Will do when I take it apart again.

 

[vRSG60]

Basically it’ll look like this.

 

[retiredNH]

What about the housing (i.e. the rest of the rear hub) that the axle and bearings go into? You wouldn't normally expect a bearing that handles side thrust as well as radial thrust to be fixed on an axle. You'd expect it to be fixed against the other member, the housing, so to speak. You might note that this is exactly how the old loose ball bearings worked - the balls were held between a cone on the axle and a cup on the hub.

 

[vRSG60]

It’s not fixed on the axle the axle slides into the bearing bore. The outer diameter is pressed into the hub.

 

[retiredNH]

It’s not fixed on the axle the axle slides into the bearing bore. The outer diameter is pressed into the hub.

Yes. That's how most bearing setups work. It's also why there should be a torque specification for the nut you tighten to hold things in place. Essentially, the hub is the spacer you're looking for. Does that make sense? If so, please do see if you can find a torque specification for tightening. Otherwise, you need to use old manual methods, where you tighten until it binds, then back off. But the old manual way won't be the best for bearing life.

 

[vRSG60]

OK will do but I’m an engineer and it’s not the way I’d do it. I’d have a sleeve inside between the two inner races to tighten against, otherwise you’re trying to press the inner races out of the bearings.
Plus I’ll need a torque spanner not a wrench not something that’s common.

 

[retiredNH]

OK will do but I’m an engineer and it’s not the way I’d do it. I’d have a sleeve inside between the two inner races to tighten against, otherwise you’re trying to press the inner races out of the bearings.

The reason bearings are designed this way is because you want to pre-load the bearing, which means putting pressure between the inner and outer races so the balls are never loose. You want to pre-load above any expected load levels. That's also why good systems have torque specs. If you did it the way you suggest, the outer race would be floating. In something like a bike where there is side thrust too (think bumps...) that would be a problem.