Anyone know the difference between the chainring spacing of the Shimano 9spd and 10spd cranksets? It is very very hard to measure. I am trying to shim a 10spd compact chrankset to work better on a 9spd setup. Without shims, the chain rubs the large ring (while in the small ring) when in the 11T, 12T & 13T rear. I can live without the 11T, but I would like to get the 12T and 13T back.