CorvetteForum - Chevrolet Corvette Forum Discussion - [ANSWERED] C6 ZR1/Z07 Rear Brake Rotor Discontinued?

The original question is here.

Quote:

racerns asked:
It seems that C6 ZR1/Z07 carbon ceramic rear brake rotor, GM OEM part # 22805790 and AC Delco part # 177-1121, is showing out of stock or discontinued throughout the country. Has this part truly been discontinued and if so what options do the owners of these cars that may only be 5 years old have for a compatible rotor? Are the C7 carbon ceramic rotors usable (fit) on the C6 carbon ceramic brake system? I believe the front rotor will, but the rear may be a different size.

Next part of this question has to do with the new C7 ZR1 brake pads. Are they compatible with the C6 carbon ceramic brake rotors?

Quote:

Tadge answered:
The replacement C6 rear ceramic rotor part number is 84488400 and we currently show a small quantity in stock. More have been ordered and we expect to receive those in a few weeks. Although the basic dimensions are similar, they are not identical so you can't replace C6 rotors with the equivalent C7 part.

As to the question about pads, the C7 ZR1 pads are the same size and could be installed on a C6 with ceramic rotors. However, like many of the answers to questions on this forum, changing a single part in a complex system upsets the carefully engineered balance of that system. Firstly, pads deposit material on the rotor as part of the burnishing process. That process sets up the performance of the system for the remainder of the pad's life. Converting from one composition of pad to another would mix those materials in an un-validated way and likely result in highly variable performance. For this reason, we would always recommend keeping the same pad material for a replacement. If you started with fresh rotors, could you upgrade to the C7 ZR1 pads? Yes, but the more aggressive pads would generate more heat in braking events before fading and that heat affects other components. The front rotors have a special heat treat process on the C7 ZR1 which reduces brake temperatures. The C6 ZR1 with conventional CCM rotors could be compromised by that additional heat going into the caliper or wheel bearings, potentially boiling brake fluid or damaging the caliper or bearing. The C7 brake cooling system is designed to dissipate that heat while the C6 system is not. Finally all our chassis controls are calibrated with an assumed frictional performance by the brakes. ABS, traction control and stability systems would all have performance compromises.