I’ve got a new set up I’ve built up with a KH 36 frame and Nimbus ISIS normal width hub that is causing me some grief. Thought that someone might have some thoughts or expereince with this issue:
The KH bearing holders don’t seem to completely eliminate movement between the outer bearing race and the frame’s bearing holders. It shows in the form of more side to side wobble at the tire than I’d expect, enough to make rubbing on the Maggie brake pads an issue when idling (even with the brakes adjusted out where they barely make contact with the wheel).
When I push the tire/wheel side to side in the frame, and watch and feel closely what is going on at the hub, I can see and feel the bearing moving with in the holder and the crank arms move slightly side to side too with the side to side pushing too.
Other data:
I’ve built a relatively high tension 4 cross wheel (with 14 ga ss spokes, Semcycle XL nipples, second generation airfoil rim, both spoke head and nipple washers) So the lateral play at the rim is (or should be) very small.
The side to side play seems to be there regardless of how tight the bearing caps are although I notice the movement somewhat less when the bearing caps are tightened down tight enough to keep the wheel from rotating freely (It appears to be compressing the outer bearing race a bit)
The bearing holders appear to fit the bearing well and the caps even take some persuasion to come off the bearing when I remove the wheel.
If you guys can’t set me straight on this, next I was gonna use some plasti-guage http://www.plastigauge.co.uk/how.html to measure the assembled clearances or use an imporvised transfer dye (think carbon paper) to see where the bearing contacts (or doesn’t contact) the bearing holders. My other thought was: the backlash/slop in the cheaper bearings on this hub might magnified with a wheel this large?
Any thoughts? Anyone else had this problem?
Thanks,
Brycer1968
My guess is that the bearing are 40mm, and the holders are 42mm, or something along those lines. You could make a shim out of a drinks can or rubber like the ones supplied with Koxx unis.
This seems odd, are you sure that it is the bearing slipping in the housing and not the bearing slipping on the axle? If it is the bearing slipping in the housing you could try jamming something between the bearing and either the inner or outer lip of the casing, If it is slipping on the axle you could add more spacers.
I never really understood having spacers for an ISIS setup as it is a tapered spline. Unless everything has perfect tolerances they would either prevent the cranks from going on all the way or leave room for the bearing to slide anyway.
You could try putting another ISIS wheelset in the frame and seeing whether the problem is still there. Then you’ll know whether its the frame or the bearings which is causing the problem.
Yes, will try that tonight Tony. I did ride this on a 100k this weekend and the flex seems to be less annoying than I originally thought. I adjusted the Magura brake to accomodate idiling, with greater clearance on the side I usually idle on - and I’m feeling much better about it.
I’m wondering if anyone has had issues with Maggie brakes rubbing with this hub/wheel/frame set-up and what solutions you found?