I have a 2006 F150 STX, I put a leveling kit on it and blocks on the back. I was wondering how big of a tire I could go with without it rubbing. Can someone please help me out?!

 

Lt275/65r18/c

 

Is it 2wd or 4wd? You could run a 33 inch tire without any issues. Possibly push a 34 inch but no more. I have 275/60r20s (33 inch) on my 2wd with front level and rear 1 inch block look normal and fit normal no rub no issues. Keep a check on width though nothing crazy on a aftermarket wheels you will be fine. Do something in the 275-285 range for 18s.

 

It's 4wd but I have 265/70/17 right now, I still have the stock wheels that came on the truck.

 

4wd shoot you can run 35s man! Seriously you could pull off a 35 inch tire with a leveling kit on a 4wd, just beware on aftermarkets might get rubs or could possibly get a rub but I doubt it, I honestly think you wont get any rubs but there might be people who say you might or will. Go for it!