I need new rotors but I was currious about mixing say Hope's Aluminum/Steel 160mm rotor with my XTR brake calipers. I don't use centerlock Shimano hubs. I have the Hope pro II hub rear and Cannondale lefty front hub. So I'm saying, I have the 6 bolt system. And I use 160mm rotors now. Is the only difference going to be in the thickness of the rotors?