[HypermilerAX]

I think it's also about inflation pressure. I used to have Continental's Supersonics for races. They exist in 20 and 23 mm, but have different sidewall max's, 145 psi for the 23 mm and 175 psi for the 20 mm. At their respective maxs, I found the 20 mm to be better even at low speed. Plus the better aero and less weight. However this works only on perfect road surface. The 23 will be better on unperfect roads.

If a wider tire rolls better than a narrower tire, the surface of the contact patch being the same (same pressure, same weight), it's probably because the tire deforms less in the width than in the length. I guess that's why the tall and narrow concept will be the future according to industrials, less deformation in width and in length (larger diameter = smaller angle).