I just have stock 265/70 R17 on my Z71, but here is a guy who put 315/75 R16 (34.6" diameter) under his 04 Silverado 2500HD...
Hi all, New member here. Just bought an '04 2500HD 4x4 yesterday. Has anyone successfully fitted a 315/70R17 (35") tire in stock location between frame rails? Searched around for a bit and didn't have any luck. Thanks!
www.gm-trucks.com
Maybe the undercarriage is substantially different on the 2500HD where the spare sits. I don't know. Others can tell you what the deal is on ours.
Keep in mind that the wider tire you are looking to stow under the truck might cut down on your departure angle clearance. Having the spare underneath might be fine, but would it be an issue if you are hung on a rock or tree stump as a result of the spare hanging low?
If I were serious about riding trails or crawling rocks, I might think about welding up some kind of custom carrier. Rooftop? I also saw a neat discussion thread by a guy that made up a custom swing-out carrier mounted on the back bumper. That was cool!