84-88 Carrera rotors are 24mm and 78-83 SC rotors are 21mm wide so does that mean you can use the Carrera calipers on the SC rotors but not SC calipers on Carrera rotors??? Paul S.

I would use the correct rotors with the calipers used. If you used a Carrera caliper with a SC rotor the difference in the rotor thickness has to be made up somewhere. You couldn't get thicker brake pads. It might work at first as the pistons would come out to make up the 3mm difference, ( 1 1/2 per side) but I would think as you got to 1/2-1/4 of brake pad left the pistons would leak or maybe come out of the caliper........There's no reason not to use Carrera rotors with Carrera calipers......

I agree (for the most part).

Here's a couple things to ponder:

You can get a thicker pad which would be the S-Caliper pad (AP45T - T = Thicker 19mm vs. 14.5) but why...

24mm rotors are heavier than 20mm rotors. When the same (basic) caliper has the same pad surface area and the same piston size; why would you want to add weight in the absolute worse place to add it -- Rotating Mass?

I've never heard of "anyone" warping a 20mm vented rotor in a 914... ever. It is more than up to the task so, my recommendation would be to stick with the A-Caliper (SC) vs. the Wide A-Caliper (Carrera) and enjoy the exact same braking power on a lighter rotor. Lighter = Faster (read that somewhere.)

Hey Eric & jt, thanx for the replies. I understand what you guys are saying and it makes total sense. I didn't intentionaly buy SC rotors and Carrera calipers. It's just what I ended up with and was hoping they would work together. I thought about the 4mm (not 3mm as I said before, thanx Eric) diference in pad wear and just didn't think it would be an issue unless I let the pads wear down that far which I never do or would do. And if I used the thicker S pads they would be TOO thick wouldn't they? I guess I was asking if there would be any other problem pairing the two together other than the pad thickness. I wouldn't think there would be a problem as long as I changed the pads at say 50%. Seems like you would have to wear them down to bare metal before they started leaking or coming apart. Anywho, My rotors are new and I didn't want to hunt down another set of calipers if I didn't have too. Paul.

Paul,

I wouldn't do it. Here's why, from a really practical standpoint:

99.9% of the pistons I see in calipers that need to be rebuilt have a rusty sludge that I call fluid shellac on the "top 1/3rd" of the piston. In all cases, this is caused by the piston being too far out in the bore due to old worn pads and bad dust seals and bad/old fluid.

By having your pistons further out of the bore from day one is asking them to be subject to more of the elements from the start. It's a bit of a Mickey Mouse way of going about it if you don't have to and, it will shorten the usable life of the caliper.

Solution:

I have A-Caliper cores here if you want to swap for the Wide A-Calipers you have.

It's not that one is more valuable than the other, they're the exact same caliper. The Wide A-Caliper has a... well, wider spacer in it.

PM me if you want to do that. It would cost you about $10.00 in shipping. Problem solved. You get a better caliper for your application.