Alright, just did some rudimentary measurements using my old wheels and tires that are about as pushed to the outside as they can be (225-60/15 on 15x7 with 4.125 backspace). Looks like the max spacer I can use is 10mm thick, which is about what I had seen used with similar wheels on another Duster. The wheels neck down to 2.25 to grab the center cap so there's no way I can turn the hub down to go through that. The dust cap will go through there fine.



These wheels have a chamfer leading from the 2.858" bore to the 2.25 bore so just making that straight would pick up about 0.35" of the 0.49" it would need to sit on the hub. with the 10mm spacer, we'd be good.

At the same time, the center cap still won't fit so I'm wondering if it would just be better to push it all out to 2.858" and use a pull-through cap, even though I'm unsure those will work that well either since there is a chamfer where those would be pinched in.