I am preparing to add a cargo box to the rear of my 84 U-Haul
13er. The StowAway2 box appealed to me because it is shaped very similar to the trailer. I do not recall ever scraping the rear bumper of the trailer when crossing rough ground or entering a driveway, and I want to be sure to maintain sufficient ground clearance back there.
The appropriate dimension to maintain is probably an angle formed between a line from the wheel-to-ground contact point to the bottom of the bumper (or other lowest frame member) and the ground (assuming a horizontal flat plane).
Does anyone know what minimum clearance angle should be used to (mostly) avoid bumper to ground contact?
I could extend the existing wheel-to-bumper line back and keep the box and bumper above that but it might push them too high for practicality.
Any thoughts are most appreciated.