Originally Posted by
Jughed
Personally - tested and verified using months of data on the exact same course... pancake flat bike, using a power meter. I have well over 500 rides on this path as data points.
I gained about 1-1.2 MPH when switching from chunky armadillo tires to GP5000's (about .75mph), then the rest with 40mm deep CF wheel upgrade. On a more modern bike to begin with, but not a full on aero bike - but semi aero. Set PB's at the same power levels over and over.
But...
I then bought a 2001 Lemond -bone stock except GP5000's- and blew all of those numbers out of the water. Then saw some marginal gains when I put 50mm deep wheels on it.
Why? Body position. The front end is stretched out a wee bit more and about 1.5" lower.
If I swapped out to a full new aero frame and kept the same body position/50mm wheels - I would only expect marginal gains, very marginal. Especially at the speeds/watts I ride at.
Thanks so much. Yes, same here. That's for sure the reason I could out-descend almost everyone I rode with. The one exception was the local Cat 2 champ. We descended side by side. Neither of us could find an advantage their opponent couldn't match. I guess I'll stick with my old bike. The reason for my screen name is that's what some of my buddies called me when I bought that bike. They were all buying custom steel - I was the first to go carbon and yes, it did make a difference. The first time I got on it I was amazed. I'd click for the next gear and I'd go faster. I kept clicking and kept going faster, no obvious end point. I'd been on many bikes but never one that performed like that. Yes, position probably had something to do with that performance, but the bike was made for that position. I still ride with bars 10 cm below saddle, perfectly comfortable. I'm 5'6" and short legged.