The main pivot bearing on my bike disintegrated the other day for the 2nd time in as many months, 26x17x5 2rs
I think my frame might be out of tolerance for the bearing and will measure it as soon as get hold of some calipers to do so. The reason I think this is the case is due to how quickly the bearing died. Also when threading the pivot axle through the bearing without it in the frame it slides through nicely with an obvious snug fit. But when you fit the bearing in the frame and try slide it through it needs tapped with a hammer. So its like the bearing is over squeezed when in the frame. Also when you fit the bearing in the frame it feels rough and removing it again results in it feeling smooth both when checked with a finger. Again this is like the bearing is being over squeezed in the frame.

So when I get hold of the vernier calipers does anyone know what the tolerance on the frame and the bearing should be? Google threw up lots of info but it was a bit confusing!

Thanks for your help.

it’s about alignment of the various cylindrical surfaces the bearing rests on it seems to me, get some pics

what bike?

Its an Orbea Rallon.

Cynic-al – not sure what pics would do to help as we will be talking very small differences in size. The bearing on 1 side is fine but just gets knackered on the non drive side. Are you suggesting its the cylindricity that is out on the frame? As in where the bearing sits is oval on shape not round?

Nope, I’m suggesting it’s out of alignment, the shaft is not perfectly straight (to the bearing).

if the surfaces were too small/large for the bearing it would be hard to install/rattle around (and wouldn’t cause premature wear IMO)

Cheers but not sure I agree, as why would the bearing feel rough when installed in the frame with no shaft in place? But then when you remove it from the frame it feels smooth again. Hence why I think the bearing is being squeezed.

bearing won’t be getting squeezed, unless you are having to hammer it in.

I agree with Al that there is some sort of alignment issue, or it could be a pre-load issue.

A photo would help to see how the thing is assembled. Is it is a shaft that goes through 2 bearings? Is the shaft attached to a swing arm or the frame? etc etc.

Bearing is being squeezed, that’s the nature of it – just matters how much.

Unless you are really having to whack it in I don’t think this is the issue…but it might be!