My AT4X hasn't arrived yet. However I drove a Silverado Zr2 for a couple days. They come with the Goodyears stock in 275/70R18 = 33".
I immediately ruled them out. Way to noisy. The truck was used with 2500 miles. I have a set of take off black 20" at4 wheels with almost new BFG ATKO2 in 33"s. I believe I am going to run those when my truck gets here.