on A 2WD BONE STOCK 33/12/50/17s will fit with the stock wheel back spacing and width...with a 2 inch spacer (roughly a 3 inch lift making the truck level) 35s will fit with hardly any rub even when cranked going in steep driveways...

http://animalhousedesigns.net/ford/after.jpg

37/12.5/17s will fit with some trimming and the 2 inch spacer but will rub on big bumps and when cranked hard

I will get a picture as soon as I can..

I tried all of these and these are my observations... take it for what its worth.

The problem people have is they want to throw on aftermarket wheels with funky back spacing so the tire sticks out and THEN IT RUBS...keep the wheels stock if you want to run a bigger tire and you wont have issues.