Chrome cannot rust. However, the surface below the chrome can rust if it has a sufficient iron content and if moisture gets to it. Normally, the only way that would happen is if you had a chip, crack or some other visually apparent defect to allow the moisture to get in.
Aluminum cannot rust. Wheels on all but the base 300 are aluminum with the Limited and C each having chrome clad cast aluminum wheels. (The chrome is not plastic, however the chrome clad wheels DO have a clearcoat over the top, which the owner's manual states should be treated the same as the paint on your car.) The stampped steel wheels on the base 300 are protected by paint. If the paint becomes damaged, it is possible for the stampped steel wheel to rust. But that's true with every car on the road that has steel wheels, and there are pleanty of them that do just fine, so I wouldn't worry about it!
It's not rusting, more like corrosion of the aluminum. Like stated before, aluminum will not rust. Although if you do not keep on top of cleaning, there will be a chance of the chrome on your rims bubbling then ultimately peeling.
Aluminum cannot rust because rust is oxidation of ferrous metals. (Metals containing iron). But aluminum can oxidize which is like rust but doesn't turn orange. Oxidation of aluminum doesn't ocurr at as fast a rate as oxididation of iron.
Im originally from Bermuda - a humid Island prone to salt spray form the ocean - oxidation of aluminum, amd other non-ferrous metals is often accelrated in these conditions, Chorme rims if not buffed and cleaned on a regular basis will bubble, pit and peel and soon corode underneath.
I thought i had escaped the wrath of the 'Salt Demon' When i moved out here to Arlington VA in the metro DC area. Teh my wife pointed out the road salts used to reduce snow and ice during the winter, this blew my mind. Damn it!
I will be taking delivery of the 1st AWD 300C to be sold here in this area - - Its Black and fully-full on loaded, it was originnally ordered by the Canadian Embassy here in DC. But they were impatient bought 2 reg 300C's of the lot. I have already had my rims and all the goodies ordered and/or delvired sitting in my garage including the custom made emblems & badges I designed .
I am now looking at what might be a really harsh winter out here so i am planning to keep the OEM rims on until Spring. Do many of you do this here in the States where you experience harsh weather? i.e. Keep the stock shoes on during the harsher months and change out the flashy rims during the 'show me' months...Sping Summer and late fall.
Anyway can't wait to get rollin i will post pics and give performancew rewies on the AWD hamdling as time rolls by.
Works for me:
Apply a coat of wax (or other paint sealant) to your chrome wheels. By doing so, you can easily use car wash shampoo (if the car is washed weekly) to clean your wheels instead of resorting to heavier cleaner.
Finally, a wax or sealant will actually apply a microscopic layer of protection to the chrome in order to help reduce any damage (corrorision or otherwise) to the finish.