leaking presta valve, are they fragile?

inaperfectworld
inaperfectworld Posts: 219
edited September 2007 in Road beginners
i've put in a new tube but it is going down slowly(115 to 40 in a week). in water it looks as though there is a leak where the valve screws into the stem. do i have to write off the tube? i am thinking to try screwing the old valve into the new tube stem. i could take it back but didn't keep a receipt . to add it, seems to me that presta valves are pretty fragile compared with schrader, the rod that sticks out on the end is always getting bent, does this matter? i had a second puncture once and on the second tube the valve had unscrewed and fallen out. as icouldn't find it the tube was useless.

Comments

  • Monty Dog
    Monty Dog Posts: 20,614
    Try and screw the valve core in firmly, or there might be a piece of dirt on the valve seat. Presta valves are better for high pressure because you can screw them closed, whereas Schraders just leak.
    Make mine an Italian, with Campagnolo on the side..
  • pw1brown
    pw1brown Posts: 243
    I'd go for a new tube. You shouldn't get many failures with Presta valves - I can remember only a couple in several years. Some makes of tube seem less reliable than others. Also, try not to attach/detach the pump at too much of an angle to the valve - straight on, straight off, as best you can.
    My bikes
  • dannygcp
    dannygcp Posts: 151
    If you got your tube from a LBS they might be prepared to exchange it for another one anyway.

    Just double check first that the valve really is faulty. I have sometimes had to really inflate inner tubes which have minutes punctures before I can find them, even by dipping them into water.

    I've used Presta tubes for years, and the only time I got a leak from the value was when I once bent the valve - which as PW1BROWN suggests was almostly certainly from pumping it up at an angle.

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