Centerlock disc rotor unharmonic resonance

[bremerradkurier]

After my second ride on a new wheelset with Shimano XT rotors and 105 calipers I now have a wine glass resonance in my front wheel where I get a tone just rubbing the rotor with a clean cloth wetted with isopropyl alcohol regardless of whether or not the wheel is installed.

Of course this outright howls when stopping even though braking isn't affected.

Didn't happen at all on my first ride, and hasn't gone away after rotating the rotor 90 or 180 degrees or swapping the rotor with the rear wheel.

Any ideas on a resolution?  Considering a thin shim between the rotor and the hub.

[jonathanf2]

I'd loosen the bolts and adjust the caliper alignment first to see if that helps. If not, try resetting the pistons back to the widest position (slightly open up the oil valve). If that doesn't help, align the rotor as best as possible and find the one section that rubs. Take a disc alignment tool and slightly bend it until the rotor looks straight. A flashlight will help to see the alignment. I recently did this aligning two disc wheelsets with 6-bolt and CL. I aligned the 6-bolt wheelset first and then proceeded to match up the CL wheelset. I found with 180mm rotors it required a bit more bending to line it up properly.

Also if it's a contamination issue, I'd try wiping the rotors with alcohol and then use fine grit sandpaper to remove any glazing. Last resort would be to slightly torch it until you see just a tinge of smoke (I use my gas burner stove) and see if that helps as well.

[bremerradkurier]

I'd loosen the bolts and adjust the caliper alignment first to see if that helps. If not, try resetting the pistons back to the widest position (slightly open up the oil valve). If that doesn't help, align the rotor as best as possible and find the one section that rubs. Take a disc alignment tool and slightly bend it until the rotor looks straight. A flashlight will help to see the alignment. I recently did this aligning two disc wheelsets with 6-bolt and CL. I aligned the 6-bolt wheelset first and then proceeded to match up the CL wheelset. I found with 180mm rotors it required a bit more bending to line it up properly.

Also if it's a contamination issue, I'd try wiping the rotors with alcohol and then use fine grit sandpaper to remove any glazing. Last resort would be to slightly torch it until you see just a tinge of smoke (I use my gas burner stove) and see if that helps as well.

Looks to be purely a rotor/hub interface perfect storm problem-as I mentioned, I can make music with the rotor installed on the hub and rubbing it with a rag moistened with alcohol.  Front/back rotor swap gave no relief; same rotor was silent on the rear wheel.