I have a stock 1999 F-150 4x4, no lift kits and stock 16" rims.
What is the largest size tire that will fit under the fenders with no rubbing? I will go with either Goodyear or BFG tires. I do not want to twist the torsion bars either.

 

i have 285 75 16s on my truck and they dont rub at all and i dont have my torsion bars cranked up at all, but i guess you can get 305 70 16s on these trucks. i also have the 16x8 wheels.
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http://www.mickeythompsontires.com/truck.html