ive got an 09 F150 lariat 4x4 screw that needs new tires. right now its got the stock pirellis 255/55R20's, nice, but i want something more aggresive. ill be installing a 2"level kit next week from rough country and i was going to buy some nitto terra grapplers a/t but im not sure what size to get. i dont want them too small or too big. i was looking at a 275/65R20 and that was a 34" diameter that what be close to my bed wheel opening.

has anyone already done the same thing with their truck? if so id like some pics and sizes if possible. does anyone think going from the 275/55R20 to a slightly taller tire will hurt my transmission?
i would greatly appreciate any input, this is my first vehicle thats still practically brand new that i purchased my self, so i'd like to keep in good running order.

thanks for reading

 

305/50R20 will work and you will only be off 3.2%. Decent traction, reasonably quiet and a 60,000 mile treadwear warranty.

http://www.generaltire.com/tires/Grabber-ATsup2-sup