Just posting this as I have seen lots of thread with guys asking the question (myself included) with no solid answers. I would say this is the largest tire you can run on a 2015+ body style dually that is stock height. My torsion keys are cranked a bit and I have absolutely no rub despite how close things are (I think they would fit without rubbing without the keys touched at all). I had to run a 1.5" spacer (hubcentric) between the duals but that was painless to install (just have to cut the wheel studs down a bit - just the unthreaded part needs to be cut).
I have happy with the look and the rear tire is not out aggressively far as I have seen with the 2" spacers. Judging by how close the inside tire is to the leaf spring, I do not think you could run any wider tires on the stock rims - I may be wrong but these are as wide as I'd be comfortable going after looking at it installed. Heres some quick photos.
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