Factory rotors have aluminum hats and the rotor is riveted to it. This is why a set of factory rotors can cost as high as a $1000 for a set.

 

Not mine - '07 530xi ,,, maybe M5's. However, the hub of a "factory" original brake disc is treated with a special coating (don't remember the name) that helps prevent rusting.

 

Mine is just a 545I and it had a aluminum hat. Maybe just the lower end ones had the cast in hat.

 

Could be ... my e60 is a '07 530xi. So, your 545 has brake discs that are riveted/fastened to an aluminum hub? Would you mind sharing a picture?

 

Sorry I don't have them any more. I changed to a drilled and slotted rotor and tossed them. The OEM are lighter. Basically the hat look like a machined aluminum and was riveted to the rotor which was a machined cast iron. Next time i see a another E60 I'll see if a picture can be taken thru the spokes.

 

Good deal! I've seen them on some M cars and but not on "normal" e60's.

 

When ever BMW Dealer replaces the rotor, do they you after market? mine was replaced by dealer under regular 4 year free maintenance, it seems to be rusting...

 

Original BMW replacement parts should be used by your dealer.

 

This has been discussed ad nauseuam. Like the other posters have said, sand them down and spray them with some caliper paint...will be good as new. And don't worry about getting any paint on the rotor itself...the brakes will scrape it off as you drive.

 

I found a pic of my 545 OEM rotors and they sure had the rivets. Frankly I was surprised to see rivets on the hat portion myself. Here you can see 3 of the rivets