Annoying friction between spokes and caliper

I have a problem with my spokes on my 36" inch wheel and my caliper of the disc brake.
I wend to the LBS several times and tuned the spokes (tighten them up) and even shaved the caliper a bit, but every now and then I hear the noise of friction between 2,3 spokes on a certain scenario positions of riding - not always.
The LBS guys said that it is probably due to the flexibility of the spokes and the size of the wheel which is something that cannot be prevented.

Of course there were several tries to position the caliper at the best possible position far as possible from the spokes but still to keep it aligned with the disc in its center.

Can anyone else share his experience with this QX 36" Disc model?

Thanks a lot,

There is simple fix: get a bigger rotor. A 200mm rotor will place the caliper.further from the spokes.

A different brake might also help.

What brake do you have?

Wow, it really sounds simple - I haven’t thought such option exists, but it makes sense :slight_smile: I guess there will need to be extensions (spacers) for the caliper mount to fit to it.
I am using the default Shimano disc brake that comes with the QA 36" Disc model - from QU-AX site it says: “Shimano BL-M-445 brake, brake-lever-mount for saddle”.
I hope it helps.

There is simpler fix: lose the offending spokes.

For a larger rotor you need an IS caliper mount to match the larger rotor, so a 200mm rotor requires a 185/200 IS mount. If you do it yourself, you will need a bearing puller to get at the rotor, then once the rotor is changed out, you need a lead pipe and hammer to force the bearing back onto the spindle.

The other option is to put thin stainless steel washers between the rotor mount and the rotor, 1-2 mm might be enough to stop the rubbing, just make sure your screws are long enough or you risk pulling the threads from the rotor mount. This would be doable without removing the bearing or buying anything other than washers and screws (if needed).

It really shouldn’t rub if this uni came disc ready from the factory. It’s possible the rotor mount was not spec’d correctly when it was machined/welded. This was a problem on some early Nimbus disc hubs, the rotor was too far outboard and so the rotor screws rubbed the frame, requiring a wider crank spacer.

If it’s only 3 spokes rubbing then I suggest that you deal with the offending spokes. Identify the spokes that are rubbing and mark each one with a piece of tape. Then try tightening the spokes opposite them one quarter turn each. This should draw the offending spokes away slightly from the brake caliper. To identify the offending spokes, apply some grease on the caliper casing at the point of contact and see which spokes have picked up grease after you’ve been cycling.
However if it’s general wheel flex then it might be different spokes rubbing on at different times in which case you might consider Bens ideas.
Hope this helps.

Guys, thanks a lot for your tips.

I actually went to the LBS to tighten the spokes (22 was the tension needed I think) but it didn’t solve the problem.
I really think this may very much be a specific model issue and I would appreciate if anyone here reading this post and owns QA 36" Disc would comment if he/ she experiencing anything like this.