A lot of what Jan Heine says jibes with my experience and I happen to absolutely love Rene Herse tires... but I still tend to take what he says with a grain of salt. Who knows what the testing "proves", there are so many variables and the results seem to me to fall within the margin of error for any testing. I might be wrong, but that's what I believe. Given that prejudice, I tend to go by my experience.
In the 90s, I used to run tubed clincher 21s with 115 psi on my road bike. I now run tubeless 28s (GP5000TLs) at 75-80 psi on my road bike. I weigh about 165, the same now as I did then (thank you cycling). In my experience, I'm not feeling appreciable more drag on the 28s. I AM definitely feeling far, far more comfortable and having far fewer flats (knock wood, I have never flatted this setup on my road bike). My modern carbon road bike with these tires gives a hovercraft-like ride, I would have killed for this while slamming over every little bump back in the 90s. This additional comfort and lack of road shock makes a huge difference in my fatigue levels, especially on longer rides. I also have significantly more grip on the lower pressure tubeless tires. Rubber compounds are better now, that combined with the larger contact patch and more compliant tire really allows you to carve corners at speed.
So, setting aside any imperceptible (to me) rolling resistance issues, I'll take a modern tubeless road setup any day.
Last edited by Hiro11; 04-09-21 at 08:18 AM.