Get a set of wheels that are 8" or wider, and rated equal to the tires you're putting on them, which is 3750 lbs each.
I went with a custom made pair of Stockton heavy duty steel 16x8's for the rear of my F350SRW. They are rated 4000 lbs per wheel. The 285's fit perfectly on them.
On the front, I run factory Ford 7" steel wheels with the 285's. The front axle doesn't carry anywhere near the weight rating of the factory wheels. The tires don't fit as well as on the 8" wheels, but with them loaded so much lighter than the rears, I run them at lower pressure and they wear even.
I would not run the factory 7" wheels on the rear with the 285's. Too much weight and too narrow wheel.
