classic1 said:
A mate owns a shop. He KNOWS the frame makes [censored] all difference in watts. He told a good customer who spends 1000s he'd get more improvement shaving his legs. I listened to an podcast with Rohan Dennis before "the incident". Done heaps of testing. I think he said the order in saving watts is position, helmet, wheels, clothing, tyres which had big watt savings and the frame was a very distant last, saving a few watts at best.
Specialized once said that in their "win tunnel" they measure gains of between 50 and 70 seconds when going from unshaven to shaved legs.
I have a "mate" than has a PhD in fluid dynamics. He designs high pressure systems for hydro cracking technology that helps make petrol from the parts of oil that were once deemed to be "left overs" and destined to go to the asphalt tar pit. Something about pressurizing hydrogen to 4000psi at 3000F and mixing it with once tar like oil at ungodly velocity. In his spare time he races and often borrows equipment for testing from others like him that have way too much disposable income. Probably knows more about fluid dynamics than a dude that wrenches on bikes. He knows his stuff that well that a presentation he did on next generations fuels got the interest on the next set of presenters - the folks from NASA that were doing the sonic boomless supersonic plane. Chats after lead to him blagging tons of tunnel time at Ames in San Jose in one of the seldom used small wind tunnels.
Chet Kyle PhD, of human powered performance and 1984, 88 and 92 TT and track bike fame, believed the the same- that the frame had the possibility to be one of the biggest reducers in drag, just shy of the best set of wheels. Funnily enough, the dude from Lotus that designed the 108 for Barcelona thought the exact same thing... If you didn't geek out on the Cycling Science magazine in the late 80's and early 90's that ended up being a weighty tome of no BS research, a good number of pics of Kyles work can be found here:
[URL unfurl="true"]https://www.sciencedirect.com/science/article/pii/S0167610520300441[/URL]
He also debunked the BS on "cross chaining" big ring and big sprocket. Loses almost no power on a well maintained chain.
While most of the drag does come from the rider, the frame makes a huge difference. I know that with the same position on my old psuedo 653 TT bike and on a Cervelo P3 - both using my wheels (28 spoke Flo 30 rims with Dura Ace front hub and PowerTap rear), I'm about 2kmh faster on the Cervelo at 300 watts but the Cervelo would give me the option to get into a better position than my old bike would allow. That 653 was 76 degree seat.