I have a leveled 2001 4x2 f150, an was wondering how big of a tire I could put on some 20" xd badlands. I know I won't have much room, but need some help, and advice on what tire. Thanks.

 

If you use a 20x8 inch wheel with 4.5 inches of backspacing you can probably fit a 305/55-20 (33x12.50) with some minor trimming, but the wheelwells will be very stuffed. A 305/50-20 (32x12.50) or 285/55-20 (33x11.50) would probably be better choices.