You MUST take the time to prep the wheels correctly if you want the paint to last. I know some have not primed, but I would take the time to do it.
I suggest this...
Wash them with Ivory dish soap to get all the grease, wax & dirt off. Then sand with 320. Clean again to get the sanding dust off - then clean with alcohol. Prime with duplicolor DAP1690 self etch primer. Then paint in the color you want HWP1xx then clear with HWP103.
demo here...
http://duplicolor.com/training/wheel..._training.html