Originally Posted by
Speedo
You are one powerful dude if those differences don't amount to much for you!!!! Using those numbers at 18 MPH the marginal power requirement for drops over tuck is 42.6 watts, hoods over tuck is 52.3 watts, and up 2cm over tuck is 59.5 watts. Any of those is a significant chunk of my power output. A set of $50 aero bars and you can hold that tuck position pretty comfortably.
Back in 2001 or 2002 Bicycling Magazine did a "bang for the buck" assessment of the most cost effective way to buy performance on a bicycle. Aero bars won hands down. The drag force goes with the square of speed, but power required goes with the cube of the speed.
Speedo
So, power in hoods is 17.4*18*1.6/3.6=139.2W
power in drops is 16.2*18*1.6/3.6=129.6W, a 10W reduction.
Did I mess up my calcs? They don't match yours.
Anyway 10W is indeed a significant value. Tyre drag is of the order of 50W, and tyre improvement can be 5-10W also.
[edit] Ah I see what you calculated. We are on the same page.