[Christ]

The frontal area isn't going to be much less because those are extremely wide tires, like are becoming more and more commonplace as replacements for duals on commercial trucks over 5 Ton.

Also, the rolling resistance is decreased with those tires as compared to a set of duals on the same axle, but I don't have numbers to cite or compare to determine if the difference makes up for a third axle vs two axles with duals. The bearings could be considered ~95% efficient, IIRC, for calculations.