Bicycle Mechanics - Deflating a tire with a busted valve stem

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KevinF
05-23-06, 06:26 AM
Subject heading pretty much says it all. My tire has a presta valve; if I unscrew the top and push it down, nothing happens. My pump won't put any / much air in. I just want to replace the tube, but there's no way I can fit tire levers in there until the tube is deflated. What other options are there for deflating tires? I'd rather not stick a knife through the tire and pop it as the tire itself only has a few hundred miles on it. Can I cut the valve stem? Would that deflate the tire?


powers2b
05-23-06, 07:25 AM
Jam a sharp piece of wire between the stem and the rim hole or cut the stem off using small bolt cutters
or a hacksaw blade.

Enjoy

AndrewP
05-23-06, 07:30 AM
Try a pin through the sidewall - that shouldnt do any damage to the fabric of the tire.


NoRacer
05-23-06, 07:37 AM
Are you using a sealant in the tire?

Check your tube for a removable valve. If you are lucky enough to have one, just unscrew it.

Air pressure keeps the valve seal pushing toward the end of the valve. Try the blunt end of very stiff wire or maybe a finishing nail to push the seal back in toward the end of the valve connected to the tube.

Rolla1990
05-23-06, 07:49 AM
A pair of diagonal cutters through the valve stem should work... That's how I deflate car tires at work.

powers2b
05-23-06, 08:09 AM
Presta valves are metal.
Car valves (Schrader) are rubber.

Enjoy

KevinF
05-23-06, 08:34 AM
Are you using a sealant in the tire?

Check your tube for a removable valve. If you are lucky enough to have one, just unscrew it.

Air pressure keeps the valve seal pushing toward the end of the valve. Try the blunt end of very stiff wire or maybe a finishing nail to push the seal back in toward the end of the valve connected to the tube.

I'm not really sure what's in the tire. There's no sealant per se, but the bike was ridden through about a 100 foot stretch of "flooded" road. It didn't look that deep :rolleyes:, so I just rode through, but it wound up being two or three inches of standing water. I have a feeling that's what killed the valve stem; I won't be surprised if it's awfully wet inside when I get this tire off. The front wheel seems to have survived fine.

No removable valve on the tube. :(

Thanks for all the suggestions!

Sheldon Brown
05-23-06, 09:10 AM
Subject heading pretty much says it all. My tire has a presta valve; if I unscrew the top and push it down, nothing happens. My pump won't put any / much air in. I just want to replace the tube, but there's no way I can fit tire levers in there until the tube is deflated. What other options are there for deflating tires? I'd rather not stick a knife through the tire and pop it as the tire itself only has a few hundred miles on it. Can I cut the valve stem? Would that deflate the tire?

This is one of the great applications for asian medicine, specifically, acupuncture!

Sheldon "Ssssssss" Brown

+---------------------------------------------------------+
| The Law, in its majestic equality, forbids the rich, |
| as well as the poor, to sleep under the bridges, |
| to beg in the streets, and to steal bread. |
| --Anatole France |
+---------------------------------------------------------+

JLauren
05-23-06, 04:23 PM
If you decide to snip off the valve stem, be sure keep one hand on it so it doesn't go through your shop window or into the face of that guy looking over your shoulder.

The Great Stonk
05-23-06, 04:37 PM
if you cant remove the valve, you need to puncture the tube, if your competant in wheel buildind/truing, unscrew a spoke and stab the tube through the spoke nipple. or try and get somthing sharp down the side of the valve and into the rubber.

DannoXYZ
05-23-06, 04:54 PM
Subject heading pretty much says it all. My tire has a presta valve; if I unscrew the top and push it down, nothing happens. My pump won't put any / much air in. I just want to replace the tube, but there's no way I can fit tire levers in there until the tube is deflated. What other options are there for deflating tires? I'd rather not stick a knife through the tire and pop it as the tire itself only has a few hundred miles on it. Can I cut the valve stem? Would that deflate the tire?How far do you unscrew it? All the way?

Also what happens with "nothing happens" when you push? Does the valve-stem go down 4-5mm so that the screw-head is flush with the tip? Or it doesn't get pushed in at all? If it doesn't push in at all, I say push harder.

KevinF
05-23-06, 06:40 PM
I wound up being able to pop the tire by squeezing a needle through the valve hole. Problem fixed.

Thanks all.

Knudsen
05-23-06, 09:35 PM
Presta valves are metal.
Car valves (Schrader) are rubber.

Enjoy
rubber coated brass