pre-dates radials in cars by a year, but interesting enough. Also, though I've seen it on every door-jamb and truckers probably are aware of it, it wasn't till I read
this that it dawned on me.
"See the number I've circled in red on the first line? This tells you that if you have this tire fully loaded with the correct amount of air in it for the weight being carried, it will measure 11.2 inches from the center of the axle to the road.
That's if the trailer is fully loaded and the tire has the correct pressure. If you find that the distance is greater, you need to let out some air, if the distance is less, you need to add air."
the tire is designed for a certain amount of hysterisis (flex), and loading it *should* be accompanied with a pressure adjustment to keep the static load radius the same.
With certain concessions of course to "overinflating" as that does seem effective/efficient to a point, and this isn't the indy 500.