Just lower air pressure to get a reasonable contact patch. What pressure are you running now? How is present tread wear?
I used to run 37x12.50x15 MTR's on 15x7's. Zero problems and drove great. I only ran about 24psi on the highway in a full-size Bronco. And I had a live front axle so that's dead simple compared to GM IFS, but still.....I also had 2.5" BS to clear 60 calipers with steelies which doesn't exactly aid handling (or at least scrub radius)
With 17's you've got less sidewall (and air volume) so you'll need a bit more pressure.
I'm again running 37's on stock 17×7.5" JL alloys. Drives fantastic....but again, SFA
35x12.5r17 vs 315/70r17
Currently I’m running the 35s on my Yukon however I found that the 315/70r17 is a little cheaper and only 1/2” smaller. Is there any reason that wouldn’t work? Thanks.
bobistheoilguy.com
You think I should lower pressure? I think I set it to 36 all the way around. When I got it they were all over the place ranging from like 28 psi to 36 psi. Don’t think the previous owner was big on maintenance.