I keep unintentionally loosening my presta valve cores with this pump head style. It’s worst with tubeless MTB stems as the white valve will spin. And it’s always at the worst time. I’ve begun using loctite on the cores to prevent this. I’m beginning to think these pump suck. Or am I the fool? Any tips welcomed!
by Free_Evidence_8012
19 Comments
Presta valve you screw on
You can screw it on. You can also just press it on so long as the presta valve is open. I haven’t had real issues since I started pressing it on. I used to thread it on and had the same issue of it unscrewing my valve core.
I have this pump head – are you threading it onto the presta valve? I’ve never had the specific issue you’re mentioning so I can only assume it’s user error. Are you cross threading it onto the valve?
Never accidentally unscrewed my valve core with mine but I also dont screw the pump on tight, just tight enough for the Oring to touch.
I have this same style pump. Make sure your valve cores are on tight, and dont overtighten the pump when you screw it on.
Are you turning it from the gold part? You should turn it from the gold part
(I have the same pump)
Get yourself a Presta valve core removal tool and tighten down the valve core a bit. If the valve core isn’t tight, a Lezyne pump head can back out the valve core when you remove it. A valve core can be tight enough to not leak while still being loose enough to back out. Been there, done that.
I have this same pump. One thought: Are the threads in there a bit chewed up and does it tend to cross thread? Might be time for a new threaded piece.
you can tighten your valve core with a small adjustable wrench. i have this pump and when unscrewing from a removable valve core i put my fingernail on it and apply pressure and its enough to keep it from unscrewing pretty much every time if i forgot to manually tighten the core.
The correct way to use this head is to:
1) throw it away
2) replace it with nearly any other pump head.
I had a pump with this head for years. I hated it the entire time. Eventually I bought a basic SKS head that clamps on and off easily. If you’re feeling fancy, you could get a Silca head.
There’s just no reason to live with this terrible head. It’s easily swapped.
Unthreading the valve core is extremely common with this head. I’d encourage reaching out to Lezyne about it so they get even more complaints with how problematic these have been.
Edit – anyone telling you that you just push this on without threading it is incorrect; you need to thread this on for the o-ring to get on far enough to create a seal
The rubber o-ring that creates the seal when you thread it on is sticking and gripping your valve core when you try to spin it off.
Spit on the tip to lube it up before you use it and your problems will go away
I’ve had this and ya you need to make sure you don’t cross thread the valve core and pull it out. Make sure you seat it properly and then screw. And make sure the valvecore is open correctly.
Happens with mine too, I’m using same pump and attachment. Lightly grease your valve stem threads (the external ones, that the pump attaches to) and use valve covers to keep clean. I use a stem cover that doubles as a valve core wrench. Hand tight and then 1/8th or 1/4 turn more. I remove and inspect whenever I change tires which is a couple times a year or so.
I like mine. I don’t do it up super tight, just enough to seal. I do tighten up my valve cores enough that they don’t come loose.
For clarity, you’re not threading onto the core, it’s threading onto the stem. It’s residual friction, or maybe a bent core, that might loosen some.
Pro tip: silicone lube keeps the bits turning nice and smooth without damaging the seals.
I fucking hate these pumps so much
Just use the Joe Blow standing pump. Has presta head on one side, and shrader on the other. Just open the presta screw tip by backing it out, and press on the pump head. It’s easy.
Depends….is your valve a Schrader, or Presta?
My lezyne does this for some valve cores but not all. I recently switched to Clik cores and it’s night and day better.