Removing 10 lbs of rotating weight is the same as removing 100 lbs of dead weight. To feel a measurable difference in mileage, it takes 500 lbs of dead weight (or 50 rotating) removal to gain 1 MPG.

Not only would fuel mileage increase, but there would be less wear and tear on components, such as shocks, wheel bearings, brakes, etc. The vehicle would accelerate faster, stop shorter, handle better........ You get the picture.

Reducing rotating weight is a good start, but, it's proven that though the higher load range tires offer reduced rolling resistance, the increased weight of the tire negates any possible benefit in that department. If you were to develop a lightweight, low rolling resistance tire, with a moderate sidewall height, it, IMO, would not be fit for installation on any vehicle that hauls any amount of weight.