Noticed on my new front rotors - 986 Forum - The Community for Porsche Boxster & Cayman Owners

rfuerst911sc · 03-11-2014, 02:37 PM

I didn't stay in a Holiday Inn Express last night

but I believe " drilled " rotors are manufactured two different ways. One is when the rotor is cast the holes are part of the casting process. These are more costly to make and less prone to cracking and are not chamfered. The second way is after the rotors are cast they are then machined/drilled. Less costly but more prone to cracking so part of the drilling process also bevels the edge of the holes.

stephen wilson · 03-12-2014, 05:13 AM

I believe that cast in hole theory is a common myth. There was actually a bounty offered on corner-carvers.com to anyone who could provide evidence of a rotor produced this way.

thstone · 03-12-2014, 07:16 AM

Quote:

Originally Posted by stephen wilson

I believe that cast in hole theory is a common myth. There was actually a bounty offered on corner-carvers.com to anyone who could provide evidence of a rotor produced this way.

There certainly are photos of rotors where the hole clearly shows signs of casting. Most seem to be high-end OEM. Not sure about aftermarket.

stephen wilson · 03-13-2014, 03:11 AM

Quote:

Originally Posted by thstone

There certainly are photos of rotors where the hole clearly shows signs of casting. Most seem to be high-end OEM. Not sure about aftermarket.

I'd love to see it. On that other site, no one could source any conclusive evidence.