This is mostly about trains, but it draws comparisons with cars:
At
10:14 there is a very interesting clip of a thin-fender era car in a wind tunnel.
Trains have drag that cars don't, like flanges squealing on the sides of the rail on corners. But car tire's tread blocks deform on corners and lift one edge. So tires performance should be different on a [industry standard 100ft] circle versus a straight track.
Oh, and he could not pull a flat car by hand. I've done so a few times, but I used a car bar.
i.ebayimg.com/images/g/B34AAOSwaB5Xqfn4/s-l500.jpg