I've studied this exact question for years and here's the definitive answer(s) using the 2000/2001 OEM 18x7 rim:

VX at 100% OEM Stock Height (non-lifted) = 275/65R18 (32" O.D.)
Some minor interior-side cladding trim will be required as VX-KAT has illustrated. An All-Terrain tire or Street version tire with smooth rounded shoulders will have less interference than a muscular square shouldered Mud-Terrain tire, so take that into consideration.

VX "Lifted" = 285/75R18 (35" O.D.)
Important Note: The 285 series width is the absolute widest tire that can still be "squeezed" onto the OEM 7" width wheel.




If you absolutely don't want to cut/trim your cladding; but are after a wider/meaner stance, then consider the tire size of 285/55R18.