Originally Posted by Steamer

Email Tim for his numbers. He's done a fair number of tests and he has pretty good agreement between them, so his numbers are reliable I think.

As for the bolded part above - yeah, this has been one of the bigger surprises for me so far. Details matter. Accessories and clothing matter. People can't hang all kinds of extra bags and lights and crap all over their bike and wear flappy clothes and big honking visors on their helmets and not expect those things to add drag. For those who don't give a damn about drag, they can keep on cluttering up the bike, but for those of us interested in speed and efficiency, the lesson is to not ignore the aero effect all of these little decisions have.