Cosmic Alloy question
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  1. #1
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    Cosmic Alloy question

    Howdy Gringos,

    I've heard that the Cosmic alloys for Renaults, Peugeots etc. are prone to porosity after many years (ie. now!), and I've noticed that one of my tyres deflates very slowly over time (I have Cosmics). Now I know this could be a slow puncture, but it's happened ever since the tyres were transferred to the wheels from the old steels.

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    As I'm about to replace the tyres, does anyone know if there's a way to seal the inside of the rims to avoid going to tubes? I assume some sort of epoxy paint might work, but I thought there might be a proper solution...

    Cheers

    Stuey


    2003 PEUGEOT 206 GTi

  2. #2
    Gone Fishin' Ray Bell's Avatar
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    I don't think the proper paint is anything all that fancy... just ask any of the wheel distributors and they should set you right... also check the bead seating to see if your air is falling through a little irregularity there.

  3. #3
    Fellow Frogger!
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    Hi Stuey,

    tyre places have stuff called bead sealer which is placed fairly generously around the bead (edge) of the rim(it's not to dissimiliar to thick black paint, but I think it may have some rubber compounds in it too). The idea being that it enables it to seal up any small holes that are allowing air to escape. However it is usually of more use when rims are old and rusty. If the rim is porous, it may be leaking elsewhere, in which case tubes may be the only option open to you!

    Hope this helps,

    Ben

    ps to get a tyre place to strip the tyre and put this stuff on they shouldn't charge you more than the price of a normal puncture repair....

  4. #4
    Gone Fishin' Ray Bell's Avatar
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    The bead sealer, as you surmise, is for the purpose of sealing gaps that may exist between the tyre and the bead... and so many wheels get rusty there... but not alloys, though they may be scratched and have small leaks.

    As for sealing porosity, there is always a way out without going to tubes. You wouldn't want to do that for safety reasons, anyway.

    Anyone who makes composite wheels will have the sealing paint on hand, too.

  5. #5
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    Exactly, Ray. That's why I didn't want tubes - the safety factor.

    Stuey


    2003 PEUGEOT 206 GTi

  6. #6
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    Cosmics were known for being porous from new. Just wondering if there is something like mousse or the old Finilec stuff that can be used when the tyres are replaced. Something decent, that won't affect the balance. Probably best consulting with a good tyre dealer.

    Simon
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  7. #7
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    Simon, that was my first thought. Some cars (and I'm talking high performance cars) don't come with a spare nowadays, but have a can of puncture repair gear. So it must be better than the old days with the instant balance problem, surely? I even think there's a Ferrari model in this category. Though, a Ferrari owner probably just replaces the tyre AND wheel (just to be safe) when they get a puncture...

    Stuey (day off and relaxing..)


    2003 PEUGEOT 206 GTi

  8. #8
    Gone Fishin' Ray Bell's Avatar
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    Finilec? The question is about porosity, that's solved by coating the rim, Finilec lines the tyre and goos everything up as well.

  9. #9
    Fellow Frogger!
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    Guys,

    I talked to a friend of mine who used to have the same problem with some alloys. He said all the tyre guy did was clean the rim (with a wire brush) and spray the entire inside of it with black spray can paint- nothing more! This solved the wheels leaking through the centres etc as they were porous.

    Maybe this cheap option might solve your problem? By the way, what is the safety issue with running tubes? or am I missing something here?

    Cheers Ben

  10. #10
    Gone Fishin' Ray Bell's Avatar
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    Yes, it's that simple, that's what I've been trying to say....

    Safety issue with tubes is that a puncture can lead to an instant deflation, whereas this is not so likely with tubeless. You can imagine the difference at speed?

    Reason is that once pressure drops there is at least the big hole the valve core goes through to allow quick leakage, but the tubeless has only the puncture hole. There's more heat buildup with tubes as well, I think.

    I have a video of Goodyear's publicity tests done at Parramatta Park with Frank Kleinig and Bill McLachlan in a Chev and a Dodge, nails all over the joint, driving over sleepers on the road... very interesting.

  11. #11
    Real cars have hydraulics DoubleChevron's Avatar
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    Hi Guys,

    why don't you just wire brush & paint the inside of the wheels with POR15. I'd be extremely surprised if it ever leaked again. The stuff grips metal in a way I didn't think possible. Great stuff!!
    http://www.ppc.au.com/

    I've used it all over my old ID19.

    seeya,
    Shane L.
    PS: You definatly don't want your tires going flat if it's on a Citroen. You see the car so dynamicly brilliant you probably wont realise you have a flat until you've destroyed the tire & the wheel
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  12. #12
    Gone Fishin' Ray Bell's Avatar
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    Rather like having a flat tyre on a tandem trailer?

  13. #13
    con
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    Fellow Frogger!
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    and for those folks that are still using TRXs (metric); putting tubes into them will definately destroy the tyres. It is verbotten! (a NO, NO)!

    I can speak from sad and costly experience.

    Sealing a leak around the rim is much easier.


    con....

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