Quote Originally Posted by Doppelgänger View Post
These days, some higher-end cars will use cross-drilled rotors to increase rotor diameter and reduce mass. BUT. These rotors, as seen on Porsches, Ferrari etc... and as well as Brembo, use rotors that are cast with the holes in place. This forms the metal grain around the holes and makes them far less prone to cracking. A rotor that has been drilled is weak because holes a drilled into the metal grain which weakens the metal around the holes.
yep exactly. people try to argue at first that these cars use the drilled rotors but they are cast and not cnc machined.