Unusual ATS wheel dated 1976

[GeorgeK]

Anyone seen this before? 1976 dated 7X15 ATS wheel with a raised boss around the valve. It has a Porsche part number as well. There is a memo available somewhere about these, made to support the valve better.
7X15 in '76 was meant to be rear wheel on the Carrera 3.o.

[75 911s]

Interesting. It's part of the wheel yes? Never seen that. My 75 factory cookies don't have them and all the cookies I've owned or seen on cars at shows I haven't seen that.

What is the Porsche part number?

Here are the variations I've found in ATS "cookie cutters"

Variations include:

A smooth transition from center hub to face, vs a more square transition.

A lip around the outer rim vs no lip

A lip where the face meets the rim vs no lip.

[GeorgeK]

Cast in the wheel, not a separate piece.

Part number 911.361.023.54

I wonder if it has anything to do with Porsche's worry about valve bending at high speed (witness the stick-on valve supports of later 7" wheels).

They are likely the first 7" wide cookie cutter series made.

[GeorgeK]

https://www.klassikats.com/technical-service-bulletin-summer-and-rim-summary-for-tires/

[75 911s]

Oh nice thanks George: copied relevant info from the bulletin:

The 7” and 8” inch Porsche rims must be fitted with valve supports, Part No. 911.361.561.00 and 01, to avoid lateral stress on rubber valves caused by the design position of the valve bore.


The 7J x 15 pressure cast rims (From ATS) will sometimes have a special cast boss in the area of the valve bore which provides safe valve support.

On rims which have this cast boss, the wall thickness at the valve hole will be so large that when installing tubeless tire valves the 3 mm wide bead ring must not be pulled through – as is common for steel rims. Pulling the valve bead through would cause excessive expansion of the valve.

[GeorgeK]

Remains the question:
Who has seen these before, who has any of them?

Porsche history has gifted us with a few of these exceptions, like the 964 prototype wheels, and the 924 turbo 6X16 forged with separate valve hole.

[kwikt 911]

I have 4 of these 7x15 bated 1973.

[GeorgeK]

OK great.
Thank you. mine are not complete UFOs, then. Not sure I want to restore them, but I won't throw them away.

[kwikt 911]

Don't know which year 911l these were on but dated 1973.....