Guys, got my 10 inch wide rears mounted. They have a 4.5" backspacing. The 295/55r15 Mickey Thompson ET Streets fit great. Looks like they will even fit lowered. I wouldn't go any bigger. The inside is about an inch away, and the outside is about a half inch.

The fronts are 8 inch wide with 4" backspacing. I found a set of 275/60r15's with a 2100 pound weight rating. They are close, but will fit inside the fender if I ever lower it.

The moons aren't on yet. This is just to show how it fits.

F100 Wheels Mounted - Imgur

 

Yea 295-305 is about as wide as can fit comfortably. Any wider and you start running very tight on one side or the other. I had them on the front and back for a little while in a 31x11.50r15 package. They fit on the front ok, but were tight. On The back they were fine.

 

Looks great!

I've got 275/60 R15 MT Sportsman ST on all four corners because I have 8" rims. The truck doesn't seem to feel planted when going ahead fast. I'm wondering how your set up feels. I don't know if it's because all four are the same size on mine or if you can run the same size on the front with the wider rears helping out.

 

Feels great on the highway. Haven't blasted down any back roads yet.
I bought passenger tires rated at 2100 pounds for tthe front. Should handle much better than truck tires.

 

I have 275 and 235 tires and I'm lowered. The only issue is that I can't get the rear wheel out unless I have the frame on stands, allowing the axle to lower. There's a guy on here who goes by instig8r63 that has or at least has tried wider yet tires in the back.

Attachment 290672

 

I'm about 95% sure you gave me the measurements of your wheels on another website...