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Problems inflating tires with Presta valves

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    Problems inflating tires with Presta valves

    Just got a pump with a Presta valve on eBay. The pump seems to work great but the air isn't gong into the tires. The pump doesn't have a lever to lock the head onto the tire valve and I must be doing something wrong. Any trick to this?

    Hi, and welcome to the forum. Presta valves don't have a spring in them like car air valves (Schrader), to keep them closed. Instead, on the top of the valve stem there's a tiny knurled nut you need to loosen gently, by hand:

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    Once you loosen this valve nut, usually you just push the pump on till seated, and then pump. I found it best to keep a hand on the end of the pump, with some fingers on the valve stem, making sure I wasn't pushing too hard on the valve stem while pumping - it's somewhat fragile and won't tolerate a lot of side force. Once the tire is up to the hardness/pressure you want, tap the pump straight off of the valve and tighten the valve nut gently finger tight. Air pressure is what's keeping it closed.

    If you've done all of these steps and you still can't get air in, you may need to break the valve free by quickly tapping on it, letting a little air outwhile the nut is loose.
    Last edited by ncmired; 03-17-2023, 07:12 AM.


      or You could do what i did and just replace the inner-tube with ones that have standard shrader valves . I did because I found mine leaked no matter what I did , so I dumped those presta valves


        FWIW - My Lezynes all thread onto the presta


        • ncmired
          ncmired commented
          Editing a comment
          That's the way my CO2 valves work. The Silca pumps of old I used to have (frame & floor) just pushed on.

        • AZguy
          AZguy commented
          Editing a comment
          I really like the Lezyne pumps... they are no more expensive (frankly they are inexpensive) than others and the quality seems really high... they just work very well and feel great in a sort of sensuous way lol

          Not that I have much opportunity to use them... I haven't gotten a flat in at least six plus years and the only use they've gotten is on other people's bikes for the most part...