Originally Posted by mpatch
physics would say bigger rotor = more stopping power given everything else being equal
yes, I am with you on that....somewhat. But, the bigger rotor on the X vs the R is more for, less brake fade, due to the chances of the X using its front brake more than the R, in its typical riding environment. The calipers and pads, sans mounting location, should be identical, as far as function. If I am correct, surface area of pad, does not care how big the rotor itself is.
Bigger caliper, bigger pad and
bigger rotor, would make for "better" braking, IMHO.