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my Sons 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?


share|improve this question
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. – Daniel R Hicks Apr 1 '12 at 14:44
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. – heltonbiker Apr 1 '12 at 17:01
If it is a Presta don't forget to remove the retaining nut before cutting it off. – mikes Apr 1 '12 at 21:45
up vote 3 down vote accepted

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.

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If I'm not mistaken, the OP mentioned presta valve, and your images look like referring to schraeder valve? – heltonbiker Apr 1 '12 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 '12 at 18:04
either way.. assuming you can do this for presta or schraeder I am not fussed, the advice seems good to me. I need to go to the LBS tomorrow AM as do not have that tool. – Jon Apr 1 '12 at 20:47
@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. – Daniel R Hicks Apr 1 '12 at 22:25
@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 '12 at 2:40

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