My Son's bike has slime inner tubes. The bike has been sitting in the garage since last summer and the front tyres valve now seems blocked. Its has what feels like 15-20 psi in it but I can not get the valve to let any air out or take any more in.

I have no idea at this point how to get it to unblock the valve so I can use it again. For that matter I don't know how I could get the tire off as it has a reasonable (not ridable) amount of air in it without slashing the tyres (nice kings 2.2 which are pretty new).

I have tried putting the pump on it and putting a bit of air into it to try and clear the blockage but that didn't do anything.

Any ideas please?

  • Unscrew the valve all the way, press it all the way down with your finger, install pump, and apply 100 PSI. If that doesn't free it, saw off the valve stem or cut it with bolt cutters. Until you get around to it, position the tires with the stem at about the 5-oclock position. Apr 1, 2012 at 14:44
  • 1
    I would go the bolt-cutter way too. I think old slime-filled tubes in this condition are doomed already, no need to save them. Apr 1, 2012 at 17:01
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    If it is a Presta don't forget to remove the retaining nut before cutting it off.
    – mikes
    Apr 1, 2012 at 21:45

3 Answers 3


Use a valve core tool to remove the core of the valve, and then clean it using a light solvent.

Valve core tool Schraeder Valve Core

It should be only a few minutes work. If there is a lump in the flat tire, the slime may have hardened, and the tube may need to be replaced, either way.

Hope that helps.

N.B. If the tyre is still inflated, you will get a geyser of slime when you remove the core! So best to do this outside

  • If I'm not mistaken, the OP mentioned presta valve, and your images look like referring to schraeder valve? Apr 1, 2012 at 16:09
  • Even some presta valves have removable cores. I did specify Schraeder valves in my answer, though. Btw, the valve core in the left side of the right hand photo is a presta valve core.
    – zenbike
    Apr 1, 2012 at 18:04
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    @Jon -- I've never seen a Presta with a removable core. I suppose they do exist, but they're rare as hen's teeth. And if you do happen to have one you'd need something different from the Schraeder valve tool (which is more readily available from an auto parts place) to remove the core. Apr 1, 2012 at 22:25
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    @DanielRHicks: They're not all that uncommon. Just not commonly noticed. And slime tubes, in order to have slime in them, are usually removable cores. It doesn't require a special tool for presta, and you can tell if they are removable because it will have wrench flats on the side of the core, just above the stem, and just below the locknut of the valve.
    – zenbike
    Apr 2, 2012 at 2:40
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    You can get those valve core tools for cheap, 4 for a dollar sometimes (dont think about using the plastic ones that come with slime, they break off in your valve and are a pain to get out). Go to a tire shop like Big-O or even a Walmart with a TLE and ask for a used valve, they usually replace your valve with a new tire. Take the valve and shave off the rubber around the bottom and superglue the core tool to the valve, wait for it to dry and stick it in your coin purse. I always carry mine with me!!
    – BillyNair
    Jun 1, 2012 at 6:55

Here's what I did. I have a Schrader valve so I remove the core as mentioned above. Then, I took an old fondue stick that I had and I used a wire cutter to cut off the fork end. This was a perfect diameter to then place inside the hole. When I put it in the hole it was hard to the touch so I gently went in and out until I started hearing a little bit of air coming out. I continue to do this until I was finally able to break through and it went into the tube. I have to note that I was lucky that I wasn't pressing too hard because if I would have been pressing harder it might have punctured the tube on the other side when i brole through. Now it works fine and I was able to fill up with air again.


I found the valve would not undo and I could not cut it so I grabbed it with a large pair of mole grips an wiggled it till it broke. Even then I had to poke the hole to let the air out. I have found that Dr Sludge tubes realy work but only last about 2 years whether used or not. So do not buy until you are ready to fit it.

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