Which brake rotors for 1971 911

[JohnJL]

Hi there,

I have a 1971 Targa that was originally a T but had a number of S upgrades ordered or added later.

The front brakes are aluminum "S" calipers. The rotors show grooving and a thickness of 20.7mm.

The Pelican catalog here shows a new thickness of 20mm which tells me I have different rotors on the car now.

Could someone pls confirm for me what the proper front rotors should be for aluminum S calipers?

John

[gamin]

AFIK all 71's used the vented rotor one size fits all. Maybe you have some aftermarket ones. My 70T came from the factory with vented rotors. Our host has them and they won't break the bank.

[djpateman]

The 20mm rotor is correct for the aluminum S calipers.

[Dodge Man]

The stock 70-73 911 rotors are factory "vented" and your difference is in the AL "S" calipers & larger pads. Stock 70-73 911s came with vented rotors. I upgraded my 911T to the AL PMB Brembo "S" size front calipers on my 911T spindles. I do not get heat fade in the canyons even on hot days. Are you referring to "vented" "cross-drilled rotors"? I replaced my 73 rotors with stock vented rotors many years ago before the cross-drilled were commercially available at a reasonable cost. Sounds like you track/DE so the cross drilled rotors would be NIZE. My buddy's 70 has Carrera power brake conversion and that car can really "throw out the anchor" on a panic stop.

[JohnJL]

THanks for the responses guys, I think something is getting lost in translation though.

Here are some pics, maybe that will help...

I have these...





I have these rotors which were formerly mounted with the aforementioned calipers and stock pads...





The used rotors show a thickness of 20.2 and 20.7mm, which exceeds our Host's specified new thickness in my initial post where I link the catalog page. I know our host sells rotors and I even linked to the catalog page the problem is their page specs dont match with what I see on my car.

You help is much appreciated.
Which front rotors fit my application and if not available from our host where can I get them?

[E Sully]

You are over thinking this. First is that is not the correct tool to measure with. You need a micrometer and read in from the edge of the disc, not at the edge itself.
The calipers changed for the S brakes, not the disc. There are tolerances allowed, not an absolute number.

[djpateman]

Those are the late 911S calipers from 1972 or so up for the early turbos. They take the 20mm rotor. I believe they would need to be machined for the 24mm rotor. I agree with Ed that you are using the vernier incorrectly. Get the edge of the rotor within the recessed portion of the jaws at least; I also doublecheck my zero often. The S caliper uses thicker pads than the A caliper, but they are otherwise the same. I'm thinking you rotors are not worn much, and may fall within manufacturing tolerance. There are probably places around you that can grind the surfaces; i have done that before. (When I worked in a VW/Honda shop years ago the Honda rotors needed grinding true fresh out of the box; at least Honda said so.)