Loose Presta Valve Core

Easyriding
Easyriding Posts: 56
edited March 2010 in Workshop
Hi folks,

Quick question - hope it's not too daft.

Removed valve cover to put some air in tyres and managed to loosen valve core. I tightened this up with my fingers and pumped air in but over a couple of days the tyre went flat.

Will I have to replace the inner tube or is there something easy I'm missing?

Any answers will be greatly appreciated.

Comments

  • Smokin Joe
    Smokin Joe Posts: 2,706
    You tightened the valve before you put the air in?

    None went in.
  • Easyriding
    Easyriding Posts: 56
    That was a quick reply. Thanks very much for that.
  • avoidingmyphd
    avoidingmyphd Posts: 1,154
    he didn't tighten the valve. he tightened the valve core. it's different.
  • pyro_maniac
    pyro_maniac Posts: 207
    Joe is right, the only other thing you can tighten is the valve stem lock ring
    valve/valve core its the same, tighten it up and no air gets in
  • avoidingmyphd
    avoidingmyphd Posts: 1,154
    No, I'm afraid you are both wrong. On some presta valves (e.g. the conti long stem ones I use, but also many others) you can loosen/tighten the stem lock ring, the valve AND the valve core.

    I persist in this argument only because the OP only actually makes any sense if he has these kind of valves, so the argument needs making if anyone is going to be able to help him.

    On that note, I can't really help with the actual question though. Basically:

    If the tyre went flat because you had the cores loose, then you certainly don't need a new tube. Just tighten them some more. I would imagine that in this scenatio you would hear/have heard some air escaping though and it would go flat quicker than a couple of days. It seems pretty unlikely to me that you managed to screw them tight to the magical point where there is imperceptible escaping air, so slow it takes a couple of days to be noticeable.

    If it went flat for other reasons (ie. puncture!), then the mechanics of your valve are neither here nor there. Find the puncture, and decide accordingly. This, I think, is more likely.
  • Easyriding
    Easyriding Posts: 56
    The prob. is not the lock ring or the valve, it seems to be the core. Yes - I did loosen the valve and air did go in.
  • blackhands
    blackhands Posts: 950
    avoidingmyphd wrote:
    No, I'm afraid you are both wrong. On some presta valves (e.g. the conti long stem ones I use, but also many others) you can loosen/tighten the stem lock ring, the valve AND the valve core.

    I persist in this argument only because the OP only actually makes any sense if he has these kind of valves, so the argument needs making if anyone is going to be able to help him.

    On that note, I can't really help with the actual question though. Basically:

    If the tyre went flat because you had the cores loose, then you certainly don't need a new tube. Just tighten them some more. I would imagine that in this scenatio you would hear/have heard some air escaping though and it would go flat quicker than a couple of days. It seems pretty unlikely to me that you managed to screw them tight to the magical point where there is imperceptible escaping air, so slow it takes a couple of days to be noticeable.

    If it went flat for other reasons (ie. puncture!), then the mechanics of your valve are neither here nor there. Find the puncture, and decide accordingly. This, I think, is more likely.

    I have a small spanner made by Conti just for this job - not sure if they are still available. The valve cores have a rubber washer to seal them - is this damaged? I tries to buy some valve cores the other day, but no luck.
  • crankycrank
    crankycrank Posts: 1,830
    edited March 2010
    You can also just use a small adjustable end wrench to tighten the core. Just do it up until it's snug. No gorillla force needed. I usually have a couple of cores from old tubes saved just in case I need a replacement. Once tightened put some air in the tube and submerge it in a tub of water and check for air bubbles. Sometimes this is the only way to detect a slow leak.
  • careful
    careful Posts: 720
    Yep, Conti long valve and some others have a removable core which has two small flats on it. Just use pliers (gently) to nip it up. I found out the hard way when I punctured and tried to use my Lezyne pump to pump up the spare. All went well until I tried to remove the pump connector - the valve core came out with it! I had no pliers and would have been stranded if I hadnt had a second tube with me. I have since heard of others having this problem with Lezyne pumps/ removable cores. Solution is to make sure valve cores are tightened up, or use tubes without removable cores.
  • marts500
    marts500 Posts: 85
    i have had problems with schwalbe tubes and valves...if you put the end cap on too tight when you come to remove it..it brings the core out with it.Then you have to faff around screwing it back in with pliers etc..the lock bit at the end bends.All in all presta valves suck.The schrader valves on my mtb are simply a superior system.

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