your missunderstanding this thread. its about wheel hubs, the part of the car that the disks, wheels etc are fitted to, not the disks. disk brakes are made of exposed metal eith no covering on them and always rust, they rust in a few hours and aren't a problem. the hubs are painted and are not meant to rust but are on my seat and many others.
I know what part you mean. As I have painted mine.
It's just different people call them different things.
As a matter of interest whats the best paint to use????????
Harrarite (sp?) smooth is good and seems to stay on ok.
I found it best to apply plenty of it with a high quality brush. Two coats seemed fine. It does take a few days to dry though. Even after 24 hours, rain will cause water marks on it.