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My mini-pump has a screw-on head (as I guess most of them do) and several times when removing the pump from the valve, it's taken the valve core out with it.

The last time this happened to me on the road, I tried screwing the core in tighter and it simply sheered in half, leaving me with broken valve core stuck in the valve shaft. There seems to be a fairly narrow range where the core is tight enough to stay in place, and not so tight that it breaks.

Are there any reliable ways to prevent this, or any adapters or attachments for mini-pumps that do not screw onto the valve core? I am using tubeless tyres, so I can't use a valve without an integrated core.

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  • Your question is for tubeless, but when using tubes I just moved to non-removable valves on the bike that I use with a screw-on adapter. I also often had the core unscrewed before that. Feb 20, 2022 at 13:40
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    fwiw If you're not a fan of threaded connectors like myself, then it's actually fairly easy to find quality mini-pumps that don't use threaded connector. The ones I use come from Topeak and most of their range do not use threaded connectors topeak.com/global/en/products/216-Mini-Pumps. Last time I looked most of the major brands e.g. Birzman, SKS, Syncros, Specialized, Beto etc also have many non-threaded options.
    – shufflingb
    Feb 21, 2022 at 0:41
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    @shufflingb Over time, the seal of a non-threaded pump for a presta valve will wear out and get torn up as it's dragged across the threads of the valve both when the pump head is pushed onto the valve stem and then again when the pump head is removed. Finding out your minipump will no longer seal to the valve stem when you get a flat 50+ km from home is not good. Feb 21, 2022 at 22:02
  • I've mostly used Continental and Schwalbe tubes. I have found that Schwalbe tubes are great at retaining the valve core and I never had issue with it unscrewing when attaching/detaching a pump head. However it's a different story with Continental Race 28 tubes, every 4-5 times or so, I will need to tighten the presta valve core. FYI: I'm using a Xiaomi electric inflator that requires you to screw onto the valve before pumping air.
    – Jeremy S.
    Feb 22, 2022 at 7:48
  • Hi @AndrewHenle, Yes, the seals do wear, but then so do the seals in threaded connectors. Only reliable way to avoid pump problems is to check them with tyres pressures before each ride. fwiw, should also regulary check any spare inner tube(s) and patch kits. Pump and tube strandings definitely soul crushing events that are best avoided.
    – shufflingb
    Feb 22, 2022 at 11:21

2 Answers 2

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Threadlocker.

Or bring a valve core wrench with you. For example this high quality metal one from Schwalbe (don’t get their cheap plastic one): enter image description here

Some multi tools also have a notch somewhere for presta cores. For example the Topeak Hexus X (though it looks quite flimsy and might fail at just the wrong moment):

enter image description here

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  • This one is for Schrader, isn't it? The question is a duplicate anyway. Feb 20, 2022 at 13:24
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    @VladimirF: It works for both.
    – Michael
    Feb 20, 2022 at 13:25
  • My mini-pump has a built-in core-tool.
    – Carel
    Feb 20, 2022 at 13:30
  • OK, I thought the other side was a normal valve cap. The problem is, that I had the valve core come off even when I tightened it before screwing the adapter on. A removable core and Presta to Schrader adapters just do not work well together. And threadlockers costs tens of dollars for a bottle while a tube with nonremovable core is much cheaper. With tubeless, nonremovable cores are not an option. Feb 20, 2022 at 13:35
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    #3 spoke wrench works great for valve cores, if your multitool has one of those.
    – MaplePanda
    Feb 20, 2022 at 18:05
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Like folks have said, locktite is great (use non permanent!) and it's a good idea to keep extra valve cores and core tool with you, although a couple small allen keys + pliers will do the trick, ask me how I know. But you won't have this problem if you don't over-torque the pump when you attach it. Just tight enough to not leak is what you want, the threads should not be bottomed out. Kid gloves :)

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