I am running a 9 speed xt cassette with a 9 speed sram chain, but with 10 speed raceface turbine c/set rings. Whilst the combination works ok, I do notice that when on rears cogs 11 – 13 and on the middle front the chain rubs on the inside face of the outer front ring. I suspect that this is caused by the spacing between the outer and middle front rings being slightly less than on a 9 speed ring set.
Now I suspect there are 2 ways to tackle this problem and wanted to see what other have done or thought.
The sensible option seems like placing a suitably sized shim ~ 0.6mm between the front outer and inner rings. Some say just run a 10 speed chain, but I suspect this may cause slight issue with the front shifter as that will be slightly too wide for the narrower chain and you could end up with shifting problems?