New rear brake pads and rotors -- sound and wear pattern?

[tgb1974]

I had my rear pads and rotors replaced with OE parts purchased directly from BMW. An Indy shop did the work.

First day or so I was running them the brakes made a sound like a turbine winding down when I would apply the brake pedal. It has been about 250 miles since and that sound has become much less pronounced but it is still present, most noticeably when nearing a complete stop. I have read other posts on here that this sound is normal and dissipates over time.

I noticed that my rear rotors have a criss-cross wear pattern (see picture) instead of the circular grooves that my old rotors and current front rotors have. Is this normal? Or is this wear pattern indicative of an installation error?

Thanks in advance.

[M3SQRD]

Those are the machining marks leftover from the manufacturing process. Below is a pick of another new oem rotor showing similar machining marks. They will wear away with mileage. Rear brakes only contribute ~20-25% of the braking so it takes a lot longer to wear away the marks on rear rotors than on front rotors. It’s normal.

[tgb1974]

Originally Posted by M3SQRD

Those are the machining marks leftover from the manufacturing process. Below is a pick of another new oem rotor showing similar machining marks. They will wear away with mileage. Rear brakes only contribute ~20-25% of the braking so it takes a lot longer to wear away the marks on rear rotors than on front rotors. It’s normal.

Thank you very much for this clarification!