i have a 2001 f150 4x4 i have 265/75/16 the truck is stock (no lift) i do not want to tighten up the torsion bars how big of a tire can i put on it with out cutting any thing or any rubbing

 

I have seen 315/70/16 on what appeared to be unlifted (t-bars) and no trimming. I don't think it was without rubbing, couldn't tell. That just looked too damn big, but I also may recommend a 295/70/16 and that ought to work nice.

 

I agree, you can cram a 315/75-16 on your stock truck by using the OEM wheels but you will have some minor rubbing on the frame at full steering lock. A 285/75-16 (33x11.50), a 305/70-16 (33x12.50) or 295/75-16 (34x12.00) would be a better choice.