hi, one of the problems with powder coating is it's toughness....
if the wheels arent perfectly clean when the powder is applied, the surface contaminants heat up when the wheel is baked- this causes small bubbles, which look shit, and are slightly weaker than the rest of the wheel.. once this weakens sufficiently, it chips, water gets underneath, and weakens the powders ability to cling. You end up with a sort of film of powder coat, that is one solid piece, but does not actually adhere to the wheel's surface..
now your problem is getting the powder coat off the wheel to redo them. it need shot, sand or bead blasting, which costs money, and is difficult with powder coat....
if it was me i'd get a decent company to paint and lacquer them properly. that way, if you chip it, you can touch up (use a common car colour (ford is most popular)if possible- it's easier to get a matched touch up pen and you can get quite a few blacks and reds from halfords )
or if you change your mind and want to paint the whole bike pink, you can do it with ease
hope this helps mate