[Nick Koan]

Originally Posted by Dean

OK, it is my contention that neither the mating surface(The flat part on the back of the wheel that presses against the rotor), nor the lug seats should be powdercoated/painted. I only found one supporting article in a quick search, but recomend others do the same.

The reasons for this is that both of these surfaces are under pressure and may get quite hot at times, and you do not want the material bonding, or getting slipery, or expanding/conmtraccting and causeing a wheel to be come loose, or stuck, depending on circumstances.

I don't think I have ever seen a OE aluminum wheel with a painted mating surface, and I belive the lug seats are bare as well, but don't recall ever looking at them prior to putting them on a car. Anybody bought new non-silver wheels, and looked.

My gram lights are only silver in the lug seats where the pressure has flaked away the finish. The mating surface, on the other hand, is not finished.