I had a 2014 F150 FX4 with a 2.5" level in the front and 1.5" blocks in the back. I ran two sets of cooper st maxx 305/55/r20 on it. They barely rubbed at full lock but i put on 1/4" wheel spacers on the front and that fixed it. I go up a lot of curbs at work and wanted something wide enough to stop the rims from getting scratched all the time. I now have a 2015 f150 platinum and i put the 2.25" level on the front and 1" blocks on the back. I'm running 305/55/r20 toyo RT's on it. went ahead and put 1/4" wheel spacers on the front of it too. i absolutely love the toyo RT's and will continue purchasing them. i have 25,000 miles on them and they are still quiet and look brand new. Have seen plenty of stock 4x4 F150's with the 275/65/r20's that have no issues rubbing at all.