Oh right its a gen 2 .sorry .I put 265-70-17 on 9 inch with 4.5 backspace &-12 offset . they rubbed so I lifted it. 1.5 spacer up front and 1.5 GMC factory leaf spring blocks, that came off a friends '15 Z71.perfect fit. I wish I got 8 with 4.5 and -10 offset. I'm going to put 275-60-17 or 285-65-17 next set but I have at least another 20k left on the Hankooks dyna Pros , ride nice and not very noisey on the highway.