The tire width definitely has a break even point where wider tires are significantly less efficient than narrower ones unless you run them at unsafe pressures. More volume in the tire means that at the same pressure, there is more deflection, and deflection hysteresis in the tread, notably the rebounding of the tread behind the contact patch is what causes the rolling resistance in the first place.
Totally agree. I do think that people underestimate the width of that point tho. For most people who are not racing the suspension benefits probably outweighs the minimal aero loss, but it’s really hard to measure. I have been on fast group rides on 48mm slicks and although I get funny looks (and am not going to win many races because I’m old and lazy) I genuinely L find it easier to keep up than on 28mm tyres i had previously. Part of that is confidence maneuvering at speed on fairly crappy roads though.
RH 48mm tires at 25psi are pretty damn good on a single. Likewise my tandem uses 44's at 45psi (front, heavy captain) and the rear 53mm at 40 (light stoker).
