Steel wheels are made of 2 pieces and getting the chrome to stick in the seam when the wheel is complete is probably rather difficult. As far as I know chrome wheels are plated apart at the factory and then welded, or riveted, together on the backside.
Never talked to a shop about having any wheels plated before so I'm just guessing......
This is the problem, getting the tight space where the wheel center meets the hoop clean enough for chrome or power coating to stick. Media blasting won't do it. Possibly a dipping process will. Newly manufactured wheels with clean metal don't have this issue when they get chromed or powder coated.
I had a set of 15x7" Cop wheels power coated. I was told to expect rust to show within a year or so where the center/hoop welded section was. One year later, I had rust peeking it's ugliness out at that spot.
