I wanted to follow up with my findings. I have read many forums on here for the max tire size on the stock “2 inch” at4 and at4x lift. I have a 2025 at4x with the oem components. I was due for new tires and wanted to get something a little bigger than the tires from the factory. The truck came on the Goodyear wrangler territory mt 275/70r18, this tire was about 33.2” tall and 10.8” wide. I felt like they looked a little small on the truck. On past trucks of mine I have lifted and gone with negative offset wheels but I’ve reach a point where my at4x is my “Dad truck”. I selected the Falken wildpeak at4w in a 285/75r18. It measures to 34.6” tall and 11.4” wide. I knew that the biggest issue was going to be the UCA clearance. With the Goodyear tires from the factory I measured approximately .75” between the UCA and the sidewall. With the Falkens being .6” wider that would make me .3” closer to the UCA. I purchased some 5mm (.197”) spacers and 10mm (.394”) spacers in case I needed them to help me feel like I had adequate clearance of the UCA. I have the at4x wheels with the +26mm offset. I did test fit the 10mm spacers with some ET lug nuts prior to fitting any tires so I knew if worst case scenario I had to use them, that I would have adequate thread bite. I was able to get 11 full threads on with the ET lugs, this meets “acceptable”. With that cleared in my head I went ahead and mounted the Falken on the passenger front for a test fit. It fit! With no aftermarket wheel spacers or any strut spacers of anykind. At full lock the tire comes close to the back inside fender liner but still had approximately a .25” gap from the outside edge of the tire. I feel like with spacers it would rub there. The upper control arm has approximately .5” of clearance from the sidewall which sounds pretty close but actually seeing the gap I felt comfortable. I mounted up the rest of the tires and drove the 15 miles home from work without a single rub or worry. If anything changes I will update! The photo of the side view on the drivers side has the 275/70r18 Goodyears for reference for the starting point. I feel like the 285/75r18 match what the truck should have come from the factory with.
