Recommended tire size for tow vehicle
With Chevy I know that with 18's or 20's you end up at the same point. The 20's tires have less meat on them so the diameter ends up being nearly identical to the 18's. I'd imagine the 17's work the same as well. If not, the OEM would have to recalibrate each speedo based on rim option.
I've got 18's on my current truck. Had 20's on the previous truck. I cannot tell a difference from a functionality stand point. Only other factor to consider is whether or not there's less options in E rated tires from one size to the next.
'16 2500HD Dmax