This is why I want to replace them. Do you have same thing with your car? There are too dark, looked like overheated, but I saw same exact thing on loaner XC70 at dealership. The fist pic for rear and second for front. I want to replace front only. It seems to me 316mm, as dealer told me.
So those rotors are 316 mm, and I replaced today, took me about two hours. If someone will do that, couple tips : turn wheel if you do one same side, brake bracket bolt is hard to remove so prepare to have a good braking bar and buy pad spread that is looked like a scissors.
Oh, I forgot to mention I bought zimmerman rotors, and seems to me they are better then OEM cheap crap. After two days I can feel it a difference between OEM and zimmerman rotors, the car stops like any European car. Volvo is cheap out on this part.