In the test, they apparently isolated the wheel weight by swapping out wheels on the slower-on-paper Firefly and the bike didn't ride up the hill significantly faster.
However Jan Heine's experiments are often pseudo-sciencey and subject to rider effort. In this test, there were no power meters to show the difference in rider efforts between the two bikes. But somehow planing gives you free watts.
Jan has a PhD in a science (geo I think), and has done bike experiments with Jim Papadapolis. I would generally take his experiments over most random ones cited on the net.
Gospel truth? No. Probably not. Generally pretty good if you look at what he’s actually testing? I think so.
(Disclaimer, Jan was a teammate 25 years ago, and apart from not having talked since then, I’d consider him a friend)
This is prob the Open vs Firefly test you're thinking of: https://www.renehersecycles.com/what-makes-a-bike-fast/
In the test, they apparently isolated the wheel weight by swapping out wheels on the slower-on-paper Firefly and the bike didn't ride up the hill significantly faster.
However Jan Heine's experiments are often pseudo-sciencey and subject to rider effort. In this test, there were no power meters to show the difference in rider efforts between the two bikes. But somehow planing gives you free watts.