>aside from small things like added friction on bearings, changed tire geometry etc This is rolling resistance, it's generally proportional to weight, and it's

>aside from small things like added friction on bearings, changed tire geometry etc This is rolling resistance, it's generally proportional to weight, and it's usually not negligible for heavy vehicles: it can easily make a large fraction of the energy usage of a truck, though at highway speeds it's rare for it to be the majority of it.