I have looked into this and the 20" wheel centers I measured were not a good fit in the 22.5" rims, I don't recall exactly what aspect was off but think it was the offset primarily and possibly diameter as well.
At the time I determined that to make/modify/assemble 22.5" wheels for these AD trucks you need the centers from the factory 22.5" wheels from 56-59. Or something different altogether, but not the original 20" wheel centers.
Grigg
Grigg you are correct in your post above. American Wheel Specialist will weld that difference into the wheel and warranty the wheel. $325.00 each.
