QX frames and Q-axle hub spacing

Hi everybody,

I tried yesterday to put my 29 wheelset (Nimbus CrMo ISIS 100mm hub) in a QX frame (with magura mounts version).

The bearing holders are spaced 100mm apart but it seems that they are thicker/wider than usual making the spokes heads be in contact with the bearing holders.

Putting aside the defective frame possibility for a second, does anybody can do the following measurements on their Q-axle hub:

  • the flange to flange distance
  • the bearing to flange distance (on each side)

I know it is difficult to measure precisely on an wheelset but even an approximation will do.

Thanks :slight_smile:

Tout can find hub information on udc.uk spoke calculator and yes QX frames and bearing holders are very thick

Thanks bouin-bouin. The calculator gives 72.4 on the non-disc side of a Q-axle hub leaving 27.6 (13.8 on each side if it were symetrical).

What I am surprised is that the Nimbus CroMo is given for 74.5 meaning there’s barely 2mm of difference yet it does not fit at all. And a regular frame seems to have some clearance there (more than a mm each side).

I will measure the current clearance but I feel like I am missing something in the calculations based on these measurements…

I’m not sure of the measurements, as I don’t have any of the parts you have. But it’s a known issue that QX uses (or at least used, not sure on the RGB series parts) very wide bearing holders, and may require some filing to get hubs from other manufacturers to fit. So it’s probably not your frame being defective, it’s just how it’s designed.

I measured the flanges on my QX hub at 51.5mm center to center (with a tape measure, couldn’t fit a caliper in the wheel).

The UDC calculator lists 33 and 72.4 for the disc/non-disc side, which averages out to 52.7mm.

So the actual hub is a mm or so smaller than the UDC numbers.

Thank you very much MrImpossible for the measurements.

I measured my Nimbus CrMo hub flange-to-flange and it about the 74mm given by the calculator. And while I had my measuring tape out, I also measured the flange-to-frame-leg distance and it was 8mm. So now I know that my clearance is somewhere between 0 to 8mm (to file :p).

So it took the dremel out to strip the paint on the inside of both bearing holders. Then I took a metal file and started to file mostly the edge and top of the holders (as it there the spokes leave a mark when trying to slowly rotate the wheel in the frame for now).

I am not done because it is slow filing by hand and I ran out of time. I will post pics when it is done just for the sake of keeping this thread complete.

I am still puzzled that the Q-Axle hub manages to fit in there as-is if one of the flanges is sitting as far out (72.5) as the calculator says or I misunderstood something with the calculator values :smiley: