Just noticed this on my wheels after getting new tires on my 2917 E300. Don’t think it was dealer but can’t be sure (can’t say I looked at that wheel lately with barely driving last few months). Looks like top “clear coat” is pitting or chipping off. Doesn’t look like scratches or damage but have no idea.

 

I’m trying to buy a 2021 and you have a 2917. How did you manage that?

 

It is called aluminum oxide corrosion. It is caused by the aluminum alloy interacting with water and air, eventually it will happen to most wheels. I just turned in a BMW X5 as my lease ended and my 20" wheels were just starting to look like that near the lug nuts. One way to slow it down is to wash and wax the wheels monthly. Only way to fix it is to have the wheel refinished and painted.

 

Strange that would happen after just 4 years. Do u live in a area that uses salt on the roads? I was gonna say maybe the tire machine scraped it but maybe not.

 

I live in Central Texas and there is no salt on our roads ever and my BMW lease was for three years and they were starting to corrode as well.