Well, I'm just a simple nobody who likes to ride bikes. I can't spout no fancy numbers, or interpret charts or otherwise act like I know the "real deal" and what I'm talking about.
All I know is under me on a calm day when I'm riding hard enough to spend significant time above 21 mph (riding solo always) a deeper wheel is easier for me to carry the higher speeds for greater distance before I blow up. They actually do give the sensation of "taking off" and making it feel easier. I can usually even see a higher avg speed for that section while the HR is lower.
Case in point the old Fausto Coppi I built up last Friday and rode the first several rides on with shallow open pro rims. On the one good calm ride using these I felt really great and made up significant time on the return leg getting in the drops and working hard.
Today I did the same basic route but using a deeper set of Mavic Cosmics. The total bike weight was a full oz lighter with these wheels. Today though I felt like crap, actually took the day off work because my knees were a mess from being abused at the VA hospital yesterday. It took me about the first 5 miles before the knees stopped feeling stiff and I was about to spin freely. I still didn't feel like I had any energy though. But like a couple of days ago I got in the drops and went after it on the return leg. The long sections I cranked at the higher speeds felt easier, HR and respirations were lower, and the avg speed over those segments was higher. Overall avg pace over the 24+ mile route was higher too. Yet I really did feel like crap the whole ride. So..... I can't say with any certainty that the deeper wheels made a difference but it sure felt like it on the ride and seems to be supported by my ride data. So yeah, I'll keep me some bikes around with deeper wheels because I've experienced the same thing many times as I "upgraded" other bikes I had a lot of seat time on.
It really is a simple as that for me. It's just a given they are faster when used in the right situations.
As much so as the fact we all know red bikes are faster.
