I hope the underlying point I was trying to make, wheel inertia matters little with constant speed, but anything that starts, and stops, especially frequently, consumes power accelerating (fuel/hp) and has to give the stored energy back up under braking (heat/brakes/tires). Thinking any municipalities can see the benefits of large Alum maintenance free wheels on high use vehicles, is obviously never going to happen in my lifetime, unless looking "shiney" becomes the in thing outside the fire dept. Our understanding of why is likely where we most differ.