In Reply To:
Just because the seat tube is curved doesn't mean it acts as the same frontal area as the wheel. There is interaction between the tire and the tube itself and of course the tube has to be at least 25mm wide,[/quote]no, i am not saying that just because a seat tube is curved means it has the same frontal area as the rear wheel. but what i am saying is that if the shaping of the seat tube is done very well (as is the p3c's seat tube), then it can approach the same frontal area of the rear wheel and the seat tube begins to nearly disappear. as that's the main goal of that p3 design feature and that's why they end up with such good drag numbers.
Where would you want to swim ?