[Mahler9th]

Like many things, the answer is it depends.

Again, the age-old Puhn book goes through all of this stuff.

I am not sure about the "two outer surfaces where the pads ride," but that doesn't seem right to me.

I think different types of cars and circumstances yield different types of needs. Further, various configurations of modified Porsche street cars (made into racing cars at the extreme end of the continuum), and dedicated racing cars have been developed and optimized through many years, so there is no need to reinvent the wheel or make guesses.

The lips on the AJ USA set up may be intended to add stiffness, but that isn't crucial in this application. Also, depending on the hub/rotor parts, there can be a slight distance between the a flat backing plate and the rotor. A "gap" if you will. That is the case with my Wilwood rotors , Bilstein RSR struts and SC hubs. So for my application, I have a lip in the composite parts. The AJ USA parts came in two sizes, for two different types of Porsche rotors. They may have the lip to help with a gap as well.


Again, what we are trying to do is make sure as much of the ducted air as possible goes where we want it. If the lips add more than $0.01 of cost to the manufacture, I wouldn't sign off on it. The Bob Russo/Holbert Cool Brake kits from the 80's had just flat fiberglass. If you want extra stiffness when using a metal, you could just go to a thicker gauge.

I think two different types of clamshells have been discussed in this thread. I believe that the initial reference is to a cooling approach taken by Porsche and Porsche-supported teams for certain 911-based racers like some 935 cars. I have seen these as I have had ready access to various examples at local events and shops.

The latter reference is to a method of ducting which includes an arrangements to deal with the 911 (and perhaps 914) chassis components/geometry in routing of the air. SRP (maybe Craig Watkins, maybe Jerry Woods, maybe someone else there) came up with something they made and sold called "manifolds." I have a set of these. They can be easily made from things like alu or PVC or composite tubing. So one can make them, or when SRP sold them you could just buy some. Time versus money. Well, time, cleverness and the desire to have some fun fabbing stuff in one's shop. Lots of threads on this here on Pelican.


It is not rocket science, and we don't need to reinvent the wheel.

962 front wheel bearings likely need/want cooling due to loads created by..... aero. Ask me how I know.