Randy, thanks for addressing my "R wheels/72S" question. Let us know what Harvey says. That'll save all of us having to bug him!
Thanks again.
Jack
Randy, thanks for addressing my "R wheels/72S" question. Let us know what Harvey says. That'll save all of us having to bug him!
Thanks again.
Jack
I had a question on this about a month ago...spoke with Al Reed, and the tech guy over at Wheel Enhancement. Both said that the stem of choice is the TR415. That's what I used on my early deep 6's and the 7R's....haven't rolled the car yet....but I'm no Randy Well's either.....
Eric
Eric...Roland mentioned the "safety humps"...those are like a little internal "hump"...inside the rim, designed to hold the tubeless tires in place in case of a loss of air pressure. Rims designed for tubes don't have these "humps"...so let's say you suffer a bit of trailing throttle oversteer and spin into a cow pasture. Let's say some grass, or a twig gets wedged between the rim and the tire, causing a loss of air pressure... See the point I'm trying to make? There's more to it than just getting a stem that seals well...just my opinion, based on reading and looking at rims...
Hello
The tube Fuchs rims are without hump but they hold the tire much better then steel rims. If you ask a local tire guy to mount tires on humpless Fuchs and he knows his job he will tell you that those are requiereing hard work to come over the edge and to be beaded correct.
When Porsche developed the Fuchs rims the saefty hump was in the development but Porsche allready knew from tests on the steel rims ( Mr. Bott was the responsible engeneer ) that under hard use the tire can slip from the bed. This was a problem only occuring with the then new steel radial tires ( Nyloncord was the normal tire ).
Just recal the first tire generations where 155/165mm wide
The Fuchs rims where designed to support the then new X radials to the best and they grip the tire toe much better then a steel rim yet they still have not the saefty hump wich does not allow to use them without tube on puplic roads. Porsche just didn´t liked to be responsible for the chance that the wrong type tire was mountet bad or wrong or mechanics did shortcuts to mount the tires. ( like said it needs more time & force then on humped rims.
Im Germany there was much talk about banning tubes in HR/VR ratet tires and today the law is that you have to use tubes with old tiresystems despite there speed rating but you are not allowed to use tubes in newer tire systems ( Hump rims ).
However like mentoned before tubes are not equal and simple tubes used in VW´s do fit into the Porsche but are not as safe as the original used tubes from the correct brands.
If you compare them direct you well see and feel the difference.
Grüsse
Roland...thank you for the clarification.
First, thanks Eric, I'll look for those stems. I spoke with Harvey Weidman today, and he said that he has used stems in the early deep dish and R wheels since Michelin went tubeless in the 70's without any problems. I believe him, I haven't had a problem either. On the other hand, I understand Rolands rationale for recommending tubes. Since the wheel I was having mounted was being used as the spare, I went with a tube to make my life easier.
I will however be searching for these unique stems, since I have more of these wheels, and the correct stem seems to be gettting hard to find. Interestingly, the stem that Harvey has been using has been changed and no longer works, so he's looking for these too. Harvey told me that the correct stem for these wheels is a large diameter, 1 1/2" long, tapered low pressure stem made in China (and also West Germany). It does not have a bulge like a normal valve stem, but is tapered instead, thereby allowing the valve stem to slide half way into the hole and providing enough surface area so as to create a good seal. If anyone should find these stems in volume for a reasonable price, please post here. Thanks!
Randy Wells
Strange. I just looked at Michelin's website under Vintage, it says XWX's are tubeless - so if early Fuchs were not designed to be used with tubeless, then why did Porsche use XWX's?????
There was a forerunner to the XWX that was a tube type...forget the initials...but the XWX was an "upgrade" from an earlier Michelin, and also other brands were used on lesser models..
Original XWX's supplied by Porsche in the early 70's were stamped " TUBED". Later reproductions as now are stamped "TUBELESS". Keeping in check with the times and tubeless rims.
Rob.........
Thanks Rob, you have just saved me from spending big money on buying wrong tires. Any idea where I could get "tubed" XWX? Do Michelin still make them?
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