I did the same thing went to 35" 18" wheels on my 2500 RAM. I did not do the lift but am thinking about it. I went with the wildpeak AT3 love the tires. The spare does not fit very well and when running hot it is right against the heat shield. I have the Decked system installed and did some through bolts and a piece of unistrut on each side of the decked system to mount my bed rack and my spare tire. I also have built a 2 battery dc/dc charging system with solar power input in a Pelican case that mounts bach there as well. Seems rock solid. If I need to use the truck to haul large things like plywood a few bolts and unload these items and I'm back to hauling. I have looked at many of the options for bumpers and rear mount carriers and they all have flaws and will either break or slam into the tailgate when bouncing down the trail IMO so far. I have converted my factory spare tire area to a housing for a compressor and airtank for onboard air. I am sure this isn't what you wanted to hear neither do I. I am still searching for the "best" solution. A few things I have found that have some potential but a bit pricey to order install and hate. I am in no way associated with these products or the companies. Just some of my own research i am sharing.
Check out the deal on Rear with Tire Carrier at Buckstop Truckware
www.buckstopinc.com
www.expeditiononestore.com
Fitting a 35" spare under these Rams is always a tight squeeze, especially once you’ve got a leveling kit and bigger meats on. I used to run a 6.0 and ended up swapping the stock exhaust for an
EngineGo 6.0 Powerstroke Delete Pipe which freed up a surprising amount of room near the heat shield area. Not a perfect solution for the Ram, but it made under-bed storage a lot less of a fight on that truck.
