I did some research on the tires.
Figuring, maybe a higher than E rating on the same 225/75-R16 platform ours has.
Learned more than I thought I already knew.
E is eight ply rating, not necessarily eight actual plies.
I could not find a definite weight carry capacity for a rated tire vs a higher rating.
The info may be there, but my efforts were thwarted by my search engine?
I did find higher rated tire's in that size, but they were trailer tires, limited tread design, and I am not sure how they would work not on a trailer.
Looking at the Rickson Tire site, https://ricksontruckwheels.com/wheels-ford-e350450.php
, their upgrade in size, and H rated tires is 215/75-R17.5.
I found a tire size comparison calculator and plugged in both tire sizes.
Note, this calc did not allow the half size, so I compared between 17" & 18" rims.
There is maybe an actual 1/2" height difference between the two sizes, at least the way I discerned it. (215 tire has shorter sidewalls)
And maybe 3.5 mph difference at 65 mph on the speedometer.
My thinking is; that this is not much of a physical height difference.
Although, the tire's should carry a heavier load, and that is a safety factor I liked.
But a complete swap out to larger steel rims and tires, with wheel covers, takes this to about $4000 for seven tire's & rims, four wheel covers (I carry a spare).
I, personally, am not ready for the expense.
We are building a covered storage and cement pad first.
But it is on my want to modify list, especially if this RV is going to be with us long term.
We are but maybe 6 months into it, and like it so far, so much so, the 5 Star tune has been done.
I should have gotten one a lot longer ago! LOL
That said, not regretting the motorcycle, pulling a trailer, tent, coolers, cooking gear, in tow scenario, that I still like to do.
However, the RV is easier! (did I just say that?)