Reid, that bicycle rolling resistance site found balloon tires (Schwalbe g one speed) that rolled just as well as thin racing tires. The real drawback is in acceleration, which the motor handles.
Which is why ebikes are spurring new bicycle design - high speed balloon tire bike. Right now you have to use MTB gear for that, but with ebikes now at 10% of new sales, that should change soon.
Rolling resistance:
Rolling resistance is extremely low. At the low air pressure of 25 psi, the Big One dethrones the Continental Speed King II by 3.3 watts (15.8 Vs 19.1 Watts). What's even more surprising is that at the high air pressure of 55 psi, the Big One with a 225 grams butyl inner tube has less rolling resistance than a Schwalbe One V-Guard or Continental Grand Prix 4000S II road bike tire at 120 psi!
https://www.bicyclerollingresistance.com/mtb-reviews/schwalbe-big-one-2016
Fascinating true science. I did not know that anyone was making an idealized balloon tire today!
Nine years ago, before the fat tire was much appreciated, I ran the
Bontrager Big Hank (no longer made, 2.5" wide by 26" ; very thin, no tread, with a supple, high thread count sidewall. Local thorns punctured it frequently.)
It was impressively shock absorbing. The front could be run with very little pressure,
Rolling resistance of a fat balloon tire is lower than that of a narrower tire IF the balloon tire is thin, supple. IF we are not constantly flexing a thick sidewall, thick tread, knobby projections. Rubber requires a lot of energy to constantly flex. It is a lossy material, it is not so elastic as hardened steel. Flex of the casing is largely converted to heat. While the air pressure inside is pretty darned efficient, the working of rubber and fabric plies can be very lossy. Hence, the fact that airless tires are not energy efficient compared against pneumatic.
So, because of the lossiness of rubber and fabric, two disparate materials calendared together, the thinner the tire, the more supple the tire and less lossy. Wider tires have lower rolling resistance if other things are equal. And below about 20mph where wind resistance has risen to be a real drag, the wider tire has no disadvantage against it other than it being more likely to pick up a puncture!
I am going to try tubeless in a week. Will report!
Supple tires without thick and stiffening tread protection will definitely be more fun with a 24/7 sealant on duty inside!