Is it doing this with the cassette installed, or with it off? Because there is a spacer needed behind the cassette if you use a campy 11 speed freehub on an older mavic wheel. If you don't use the spacer, the inboard side of the largest cog can rub on the hub shell.

As well, just in case, here's the excerpt from the manual. I know you said you put the washer in and tried another, but that symptom is exactly what happens without the washer.

http://www.tech-mavic.com/...ocs/products/2_4.pdf


For the full set of Mavic service info go to:

www.tech-mavic.com

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password: dealer