This is interesting to me. I've been riding a Guru steel with 50/34 (10 sp) and I recently bought a CAAD 12 with 52/36 (11 sp). Both bikes weigh about 17 lb 11 oz. Both bikes feel amazingly quick and nimble. Two of the best bikes I've ever ridden. But, for reasons I cannot explain, the Guru seems to be a bit faster. I'm guessing that when I get into the higher gears I'm not strong enough to spin the 52x11 as well as I can spin the 50x11 and this actually slows me down. Would love some opinions because it's a mystery to me.