Valve stem holders??

[Semjon]

First I would like to wish everybody a great Porsche 2006!

Does anybody know of these valve stem holders:

were standard equipment or optional or aftermarket?

I rarely see them on early 911/912's

Thanks and regards,

Semjon

[pwd72s]

All 3 of my steel wheeled cars had them standard. Their purpose? To prevent the tube from rotating inside the tire..at least that's what a dealership mechanic told me "back in the day". You see, once upon a time, there was a device known as an "inner tube"....

[Semjon]

Ok, great! Thank you very much for your quick answer!

You see, once upon a time, there was a device known as an "inner tube"....

Long, long ago when they made ships out of wood or is that too far back

[Bummler]

First I would like to wish everybody a great Porsche 2006!

Does anybody know of these valve stem holders:

were standard equipment or optional or aftermarket?

I rarely see them on early 911/912's

Thanks and regards,

Semjon

When my older brother took delivery of his Irish Green '65 911 those "stem wires" were in place. The car was shod with Firestone Phoenix tires but I never knew if the wires were to keep the tubes from rotating or just retain the valve stems from the centrifugal forces exerted at higher speeds...

[Steve@Rennsport]

"I never knew if the wires were to keep the tubes from rotating or just retain the valve stems from the centripetal forces exerted at higher speeds"...

Yessir,.....thats the real reason for those supports. At very high rotational speeds, the neck of the valve stem get bent outward toward the rim and can crack the rubber or pull the stem loose from the wheel enough to make it lose air pressure. Needless to say, this would have disastrous results.

Porsche began doing the same things with valve stem supports on the '76 Turbo's.

[Bummler]

Yessir,.....thats the real reason for those supports. At very high rotational speeds, the neck of the valve stem get bent outward toward the rim and can crack the rubber. Needless to say, this would have disastrous results.

Porsche began doing the same things with valve stem supports on the '76 Turbo's.

AHA! I thought so.

As I recollect those Firestones were tubeless...

[pwd72s]

Hmmm, the "high speeds" of early 911's and 912's? My 912's topped out at 115 or so, the '70T at 125 or so. But, the centrifugal force theory makes sense as well. BTW, as delivered, all 4 of my Porsches ran tubes. '66 912, '69 912, '70 911T, and my current car, '72S. But no stem supports for the fuchs of the S, the fastest one of the 4.

[Steve@Rennsport]

LOL,.....Agreed,....those cars (except the "S") were not considered fast, even in those days.

I did not see these until the 155+ MPH Turbo Carrera was released when a Porsche factory person told me that they were required at that speed.

As the rubber valve stem ages and hardens up with heat, I'd imagine that the speed at which they can leak goes down.

[Semjon]

Great information guys! Thank you very much!

[Shawn]

And Paul is never. However, I am positive that the little wire bits were created to hold the Schreader valve stem in place. Some early steel wheel cars had tubless tire options.

As I recall this. Shawn.