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Thread: Early Fuchs - Valve Stem Modification

  1. #21
    Senior Member Harvey Weidman's Avatar
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    Cees,
    That is why the XWX was so dominating in the production classes (back in the olden days, we had to use the actual tire the car came with in the stock classes). The sidewall was so stiff, the tires almost felt like 16s when on the track. Also one of the reasons that led to the changing of the wheel drop-center design. The tires were and still are some of the most difficult to mount without damage.
    H

  2. #22
    Registry member# 206 fourteenten's Avatar
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    Thanks Harvey, good to know. I will never run this tire on a car but for removal I need to warn the guys that will try it. Is my wheel actually manufactured in 1972?

    Kind regards,

    Cees

  3. #23
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    For those who need a more immediate fix like someone stranded on a road, I have located some of the fat style valve stems you may want to put in a road kit. They are manufactured by Milton and available on Amazon at a nominal $9 + ship for 10. Here are some pictures. I put a Milton next to a current NAPA TR 415 so yo can see the fatter profile. These were on my car for 5 years before and just installed new ones on my deep sixes with re-tire and they are OK.

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    Jim Lonsdale
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    60 356 Coupe (First Car $400!)
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  4. #24
    I purchased the proper valve from Dill for 38 cents each.
    http://yourtireshopsupply.com/produc...-valve-dit15wz
    Zed

  5. #25
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    Update. Input from Michelin technical manager received today for those with early type rims facing these dilemmas. Cut and pasted here for information ....

    "In the early 1970s tyre and wheel types were indeed changing from Tube Type to Tubeless and also from Crossply to Radial. There are two important characteristics of the wheel rim and tyre that must be respected; the dimension and flange profile, and the TT or TL specification.

    · The flange profile is described by number (the wheel width) and a letter (the flange profile). The two wheels that you mention in your email, are designated 6J. The tyre and the wheel width and profile need to be compatible.

    · The TL and TT specification depends upon the design of the wheel (and the tyre). The tube is required to render the wheel, the tyre or both airtight. As you describe, this is where the two Fuchs wheels for the Porche seem to differ. I believe that one of the wheels would have a valve seat designed for a clamp in or snap in valve and so would be suitable to use tubeless with a tubeless tyre. Our data book describes this wheel as having been fitted from 1975 onwards. The other wheel is designed for a tube to be fitted and so must be used with a tube, but could be fitted with either a tube type or a tubeless tyre (owing to the J bead seat).

    · You are correct that in any case, a tube should not be fitted in a tubeless tyre if the inner liner of the tyre is roughened or ridged as part of its manufacture and design, since the tube can chafe on the high spots of the inner liner during service which may eventually lead to inflation pressure loss.

    · It is not normally recommended for tubes to be used in tyres with aspect ratios less than 70% (the Michelin tyre dimension for the 911 at the time was 185/70 R 15 and a 15E9 tube was available).

    · Our technical advice in 1975 was that tubeless radial tyres should only be fitted to cars that were originally fitted with tubeless radial tyres by the manufacturer and that the wheels must be those originally fitted by the manufacturer.

    · The humps that you describe are designed to hold the tyre bead in position on the wheel in the event of reduced inflation pressure or extreme lateral loading. It is likely that only the later tubeless wheel would have been manufactured with a hump."


    While I am no expert from what I read above there doesn't seem to be a configuration that enables the older wheels to be used with current tubeless radials that adheres to rules, advice and guidance, unless I am misunderstanding it? Even more so if 60 profile on tube type rims without humps, it seems?

    I understand Fuchs wheels with humps appeared on 911 few years before 1975 but intrugingly this input is referring to Michelin technical data archive information around the same period that Snodgrass notes " April 15 1975 XWX 185/70 VR15 tires are switched to tubeless version" which along with many detailed comments presumably is based on his access to factory production running changes when writing his 2.7 Carrera book.

    The main thing is everyone remains safe / legal in their choices. Each owner will need to make up their own mind based on current qualified expert advice and their particular country, car and rim and tyre circumstances (as previously mentioned I'm certainly not a tyre or rim expert so not offering advice on these matters). I thought it might be interesting to share this input from Michelin in the UK, the tyre company usually credited with commercialising radials.

    S
    Last edited by 911MRP; 07-04-2018 at 08:48 AM.

  6. #26
    Senior Member HughH's Avatar
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    Steve
    I am no expert either
    However on both the deep 6's I used to run, and now the 11 72 dated flat 6's I have (both of which have had 70 series and the deep 6's also had 65 series tires) I was told by the tire experts here to NOT use tubes with modem tires but so long as I had the correct valves that fully sealed the wheel (and there were no porous parts of the wheels) tubeless was much safer than modern tubed tires. this may be to do with the roughness inside them but I recall being told about the risks of tubes rotating inside the tires and pulling the valve out. I note this sentence in the reply you have " I believe that one of the wheels would have a valve seat designed for a clamp in or snap in valve and so would be suitable to use tubeless with a tubeless tyre."

    There is no doubt that the deep 6's are difficult when it comes to having a valve that will stay in place (as well as getting the tire on or off properly). The flats are not so bad and I have never had an issue with finding (being supplied with) valves suitable. (it helps I suppose that the person who does my tires specializes in Porsche, Ferrari etc tires from the 60's and 70's.)

    So after initially (in the early 90's before using this person) having tube tires I have run tubeless ever since with (touch wood) no issues from doing so. The couple of times I did get a puncture (both with a nail or screw) I was told I was lucky to be running tubleless as a tubed tire would have deflated much quicker

    I also repeat your disclaimers about not being and expert etc etc
    Hugh Hodges
    73 911E
    Melbourne Australia

    Foundation Member #005
    Australian TYP901 Register Inc.

    Early S Registry #776

  7. #27
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    Image of old leaflet on 215/60 15 VR tube and tubeless posted for historical interest only. Standards and recommendations on tubes and tubless tyre sizes have changed particularly regarding tubes on lower profile tyres such as 60percent. Evidently in 1977 215/60 15 Dunlop SP Sport Super were still available as both tube-type and tubeless, according to this old leaflet.
    German language so comments need translating.
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    I understand that Porsche at one time fitted tubed type before switching to tubeless sometime during the 2.7 impact bumper era ( as covered in my other posts). I certainly wouldn't fit tubes to 60 profile these days other than for static display for originality and suggest properly qualified expert advice is taken on such safety critical matters, rather than relying on old historical papers for current safe tyre fittment practices.

    Pictured below these ancient 215 60 VR 15 Dunlop Sport I have on shelf Dot code 424
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    Compared to my tube type German made Pirelli 215/6015 even more ancient dot code 404. Pirelli 215/60 15 VR of this tubeless type were original fit to my car according to handwritten note on factory papers in car history file.
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    Shared on this thread for those who might be interested in old tyres and tyre company papers of 70s -- as it once was.

    Steve
    Last edited by 911MRP; 10-13-2018 at 06:48 AM. Reason: Add photos

  8. #28
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    This paragraph in a long term test test from of 66 car dated 1970 refers to Porsche not recommending tubeless and loss of pressure due to time when switching to from tube original fit to tubeless Firestone of that era. The full article us elsewhere but the extract with its observation back in the day also relevant to also post here Name:  image.jpeg
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  9. #29
    Quote Originally Posted by greens View Post
    I have located some of the fat style valve stems you may want to put in a road kit. They are manufactured by Milton and available on Amazon at a nominal $9 + ship for 10. Here are some pictures. I put a Milton next to a current NAPA TR 415 so yo can see the fatter profile.
    greens,
    Is your Milton valve the one on the right in your first picture?

    I have just purchased Milton TR415 (pack of 10) from Amazon U.S. but they're slimmer (made in China) than the one in your picture. I'm sending these back for a refund.

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  10. #30
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    This is the valve to buy, but from where?

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