I know stock I have 16x6's but a guy has a set of nice BFG MT 31x10.5x15 for sale locally for a good price. Can I put a 15" rim on an 89 F250? If yes, what rim size would I need for these tires including backspacing? I'll probably just buy a set of steel 15x8 white wagon style rims for cheap if I can use the 15" rims.

 

I don't think anyone makes a 8 lug 15" wheel. It wouldn't clear the caliper unless it was spaced way out.

 

I thought maybe the older 70's F250 would.

 

They make 8 on 6.5 15" wheels but I doubt you'll get them to fit over the Ford twin piston calipers and big rotors. I know they'll fit on a GM if you grind the calipers, but the GM caliper is the same between the 1/2 ton and 3/4 ton applications, just the rotor is different. Our brakes are way better than what game on the 73-91 GM's

 

Looks like I'll just have to find some decent 16" tires.