I am doing some brake upgrades and I would like to know if the pistons on a Carrera ('84 - '89) rear caliper are deep enough to not cause a problem on a 290x20 rotor vs the correct 290 x 24 Carrera rotor.
My objective is to increase my rear brake bias without adding significant unsprung weight. I know the Carrera rotor will provide a larger heat sink, I just want to see if I can get by with the existing 20mm rotors. I may also have to do the MB master cyclinder upgrade.
Thanks,
Joe Rausa (jrausa@orchardpump.com)
1970 911 w/2.7
16" Fuchs
Bremtek 4 piston front calipers (know you know why I need more rear bias)
porterfield RS-4S front pads
non-boosted brakes
19mm MC

 

You just need to change the pads before the last 2mm of normal wear. You want to keep full or at least half thickness pads for heat issues anyway.

 

Thanks Bill. That was the information I was looking for.
Regards,
Joe

 

If the factory rear SC rotors are 20mm and the factory rear Carrera rotors are 24 mm, why not use brake pads that fit a 911S (alloy caliper)? They're designed for a 20mm rotor, but they're thicker than A caliper pads. Perhaps the combination of Carrera rear calipers with thinner SC rotors might create enough room for the thicker pad; then you wouldn't have any problems with extending the pistons too far.

Does that sound right?

Sherwood

 

If the front S pads fit in the rear M Carrerra calipers, that might work. The S rotor was the same thickness as the other early vented rotors so the issue is whether or not the 13mm S pads would fit into the calipers. Good thought.
Thanks,
Joe