Digging around some more, it looks like to get a higher rated rim, I would have to go with a trailer rim. Found a 16x7 8-165.10. What is the difference between a truck rim and a trailer rim? Can it be done? Should it be done?
Edit, friend of mine who runs a tire shop said don't use trailer rims on driven axles, not rated for safety and such.
Back to the grind of finding a suitable rim, or a drw axle...
Below, I am talking trucks/trailers with 16-inch wheels --- just to be clear.
I have made most of my living pulling big cattle trailers, horse trailers, and long flatbeds and I have NEVER seen any trailer with a wheel more than six-inches wide unless some knot-head put them on there.
A seven inch wheel looks plumb goofy on any trailer as it puts the sidewall out past the edge of the trailer fender or flat.
What you have is a common as dirt "Wagon Spoke" wheel made by a gazillion different companies for use on SRW 3/4-ton trucks.
The examples you have are stouter than most due to the way the center has a rolled edge and is pressed into the rim and they look fairly thick.
In use, no matter what any numbers may say, they are probably stouter than the Accuride wheel, which is fairly stout.
The stoutest of the stout O.E.M. wheels were the earlier Ford Firestone wheels, 16x6; one of those will outweigh an Accuride by a bunch; we are always keeping our eyes peeled and grab any we find as they will outlast anything else in heavy hauling using 8-on-6-1/2 wheels/axles.
As for your question "What is the difference between a truck and a trailer rim" --- the answer: nothing; many trailers have the same wheels found on many trucks.
If there were an actual difference between truck and trailer wheels, I would say a set of wheels for an 8,000-lb Dexter would be a lot stouter than a set specifically for an F-250; but then, you can also get an 8-lug 5,200-lb axle and it will have the exact same 8-lug wheels as the 8K axle and probably no different than what you will see on many trucks.
My own honest opinion and exactly what I would do were it mine = the first thing I would do is stay as far away from any steel-belted radial tire as I could.
Those paper-thin flimsy sidewalls are where most of your squirming around is coming from.
Yes, I know; there are millions of naysayers who would like to cram their radial tire knowledge down my throat; but, I know for actual fact what will and will not work and my personal F-350 has not had a steel-belted radial on it in over twenty years and it will out-ride and out-drive any radial equipped truck on the road.
Put you a set of BIAS-PLY tires on there and see for yourself that I am right.
DeeStone, for one, makes several tread designs and many ply ratings plumb up to 16-ply/LR-H in good old 7.50-16 BIAS
The day I got rid of the radials was the day my truck started driving like a truck should.
Aired up and side-by-side, a 7.50-16 BIAS is almost exactly the same height as a 235-85R-16; radial or bias, heights will differ between tire brands, actually quite a lot.