I ordered and received from Fastlane a pair of front rotors for my car. I ordered the ATE rotors. When I pulled them out of the box, first I noticed these things are very heavy, then I noticed they both had notches/grooves, if you will, cut into the outer edge. One rotor has a larger "notch" than the other. It looks like they remove some material. I am making a guess that this was done for balancing purposes. If so, then WOW!!. I have never heard of balancing brake rotors. German engineering strikes again. Anyone heard of or seen this before?

__________________
1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member