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Magical innertube.(5 posts)

Magical innertube.Sintesi at home
Apr 19, 2002 2:05 PM
Goes mostly flat over night but will pressure fine for a 2 hr ride. So I've been submerging it for the last 5 minutes and not a trace of bubbles. I know it's a small, small leak, but jeez nothing. Is the air permeating through the tube itself? My other tires don't do this. It's Butyl BTW.
sounds like the valvejw25
Apr 19, 2002 3:01 PM
I've had tubes do this, too. One was a tiny pinhole that only showed up under submersion, and the other was a leaky valve. That one revealed itself under submersion, but only by leaving it there for 5-10 minutes, at which point a tiny air bubble had formed under the presta "nut".
Sadly, once a valve goes anymore, the tube's wasted, so that tube turned into a bungie.
Testing 1, 2, 3Kerry
Apr 20, 2002 1:21 PM
Sometimes you really need to pump a tube "scary large" to find these pinhole leaks. I had a tube that needed to be pumped 3-4 times per week instead of the normal 1-2X, and when I left the wheel off the bike for a long time, the tire would not be soft, but flat. I finally found the leak after pumping the tube very large and then submersing in water. Just a growing bubble on the surface of the tube rather than the normal stream of bubbles, but once I put a patch on it, the problem went away.
I'll try that. thx. (nm)Sintesi at home
Apr 21, 2002 5:38 AM
re: Magical innertube.JimP
Apr 22, 2002 7:16 AM
I had a new Conti Sprinter do that. It would only go flat when the pressure started over 150 lbs while on a stretcher rim. I took the valve core out and found a little bit of adheasive on it. I cleaned it off and made sure there wasn't any more in the valve stem, replaced the core and now it is fine.