I've been curious on this as well. The only difference I've noticed is wider wheels making a better aerodynamic match to the tire (well, wider than 17c or 15c wheels).
The rolling resistance benefit of wider tires is that a skinny tire has a long narrow contact patch, which increases sidewall deflection. I'm usually on a 166mm track, so my weight is probably effectively doubled at speed. I do notice a noticeable sidewall deflection on some tires on the track (typically not for the skinny guys). I can't see my rear tire on the track (like I can on the road), but I'm thinking rolling resistance has a lot to do with minimizing tire drop. If you are over 200lbs, you are going to need a lot of air in that tire in a 2g turn.
Last edited by chas58; 06-25-20 at 08:39 AM.