Originally Posted by thewalrus
Because there isn't any weight advantage - the carbon is just window dressing...
weight weenies says:
carbon: FSA K-Force 53/39 175mm with BB: 790g
aluminum: Shimano FC-7800 53/39 175mm with BB: 779g
same with stems - there's lots of carbon stems on the market. many weigh more than a thomson x2 in the same length. for every super light carbon stem there's a correspondingly light alloy stem (syntace comes to mind).
Well, the FSA crankset, to be fair, isn't the lightest thing out there. The Stronglight Pulsion comes in well under 700 grams (probably 625 to 650) with the Twister BB.
You really can't draw too many conclusions about equipment/materials superiority by what the pro's use. They're paid to use certain products. That's the deciding factor about what goes on their bikes.