They're separate "decals" with a moderate resolution of their own. They can deform into the body during extreme crashes but otherwise they act good enough, and are readable
Tilt deck yes, it realistically would use the same rims and lug pattern and tire size however the enclosed trailer does not. As my plan was that the tire would only exist in one size, I had the opportunity to put the size and aspect ratio text on it which would make it weird if it existed in any other size. Although as similar modular steel wheels like this were on pickups and vans, I'm going to put them in a separate mod available for the 8 lug Gavril hubs (as are already visible on that army green D-series in the main post) and perhaps the tilt deck trailer then as well