tubeless valve leaking air

[Tania]

I noticed this weekend that the spin-ny twisty top thing on my presta value was sticky - meaning, I had trouble opening it and then closing it once I was done adding some air. Now I can neither open it nor close it and it's stuck in a half open position and slowly leaking air. At least, I'm fairly sure that the air is coming from the valve.

Is that fixable (and if so, how?) or should I just use a new valve stem?

[TwoWheelsDC]

Do your valves have removable cores? Replacing the core would at least be easier than having to remove the tire and replace the stem.

[anomad]

Might try using a pair of pliers to close it. Don't get carried away applying a ton of force. But you might be able to open and close it a few times and remove the gunk. Sometimes I use a rag or gloves (or pliers) to get a better grip on those little bastards when they get gummed up with Stans. Taking the whole thing apart and cleaning it later will probably take care of it for good.

[drevil]

Do your valves have removable cores? Replacing the core would at least be easier than having to remove the tire and replace the stem.

+1. After wrasslin' with gunked up cores and trying to clean 'em with little success, I discovered that replaceable cores are cheap and a huge time saver. Buy a bag of 10 Kenda cores for a little more than a buck a pop/each:
https://www.amazon.com/Kenda-Presta-.../dp/B0028N8DGU

[Harry Meatmotor]

+1. After wrasslin' with gunked up cores and trying to clean 'em with little success, I discovered that replaceable cores are cheap and a huge time saver. Buy a bag of 10 Kenda cores for a little more than a buck a pop/each:
https://www.amazon.com/Kenda-Presta-.../dp/B0028N8DGU

bikeshop trick: customer has flat tire --> after replacing tube, ask customer if they want the old tube --> if no, pull the valve core (if removable) and stash in workbench drawer.

non-bikeshop trick: call bike shop --> ask if they have a stash of used presta valve cores --> profit.

other bike shop trick: no tubeless valve stem? cut up old innertube, leaving 1 cm of butyl around valve stem. Viola! tubeless!

[hozn]

My solution to removable cores is to put red loctite on them :-). Otherwise forget using a thread-on Lezyne pump head.

(Honestly, I have never understood why people go through the hassle of putting in sealant through the valve stem.)

But in this case, certainly having a removable core might save a little bit of money. (But at $4 for a stem -- or maybe less for a tube that you cut the stem out of, this isn't a big ticket item.)

[drevil]

bikeshop trick: customer has flat tire --> after replacing tube, ask customer if they want the old tube --> if no, pull the valve core (if removable) and stash in workbench drawer.

non-bikeshop trick: call bike shop --> ask if they have a stash of used presta valve cores --> profit.

other bike shop trick: no tubeless valve stem? cut up old innertube, leaving 1 cm of butyl around valve stem. Viola! tubeless!

Nice! I've had little success removing the cores of my old tubes, most of which are Kenda or Specialized. I have a huge stack of them that I've been meaning to patch, but at this point (a few years?), I'll just try to remove the cores and recycle them.

There was one time I was going to use a stem cut out of a tube, but the rubber base was nowhere near as thick or sturdy as a tubeless stem like the Stans, so I abandoned the idea and ponied up for a real one. I assume you've never had issues doing this though?

My solution to removable cores is to put red loctite on them :-). Otherwise forget using a thread-on Lezyne pump head.

(Honestly, I have never understood why people go through the hassle of putting in sealant through the valve stem.)

But in this case, certainly having a removable core might save a little bit of money. (But at $4 for a stem -- or maybe less for a tube that you cut the stem out of, this isn't a big ticket item.)

The pumps I carry on my mountain bikes are thread-on Lezyne or Specialized, but it's rare for the valve to get unthreaded on removal. If they do, I just screw it back in. I like the ability to be able to take them off out in the field for when I'm out in the woods. On longer rides or bikepacking trips, I'll bring at least one 2oz bottle of Stans just in case of emergency.

I have a few wheel/tire combos that work fine tubeless, but they're relatively difficult to initially seat because they're so loose when first mounted. Sometimes I might have to use a tube initially or use both hands to pull the tire taut while using my foot on the compressor valve. (Note, this scenario is usually with 4" or wider tires on 65mm rims or 3" tires on 40mm rims ). Basically, it'd be very messy if I put sealant in initially.

[TwoWheelsDC]

Basically, it'd be very messy if I put sealant in initially.

While I haven't tried it the "Hans Way", I think it would be very messy for me too. I've found that adding sealant through the valve stem is pretty clean and easy. But different strokes and all that...

[Harry Meatmotor]

I assume you've never had issues doing this though?

It's more of a fix in a pinch, and I usually run three layers of tubeless tape, with overlap at the valve hole, so the cut up valve fits pretty snug through the hole poked in the tape.

I'll add to this discussion, too, that I tend to look at tubeless valves/valve cores as kinda dispensable - if they give me any grief due to gunky valve cores or bad seals at the base I just toss them out.

[Tania]

I don't have a spot at my place to even deal with sealant etc so I usually let the shop handle all things tubeless-related. However, I've been thinking about getting the SO a small compressor for his garage as an xmas present. So that then I can use it.