Seemingly strange inner tube issue

[cmbicycles]

Over the past month or two I have had 3 different tubes separate at the valve stem. No holes or tearing, just the base of the valve becomes detached from the tube. It has happened on Kenda, CST, and Specialized tubes. Wheels are H+Son Archetypes with a Zipp rim strip and Velox, and its always the rear wheel with no issues on the front. Pumps have been my shop compressor (w/ a press on presta adapter), or a Specialized air tool pro. The tube holds air fine most of the time, until exactly the moment I'm getting ready to go out for a ride and top off my tires, then it just goes flat. I guess I need to just not put air in my tires anymore.
Anyone else run into an issue like this before? I'm going to try using one pump vs. the other for a while and see what happens. I'll maybe throw the old Joe Blow back into the rotation as well.

[fogrider]

when the tire and tube are installed, do you use the nut on the valve to cinch down the tube? even thou the tube is from specialized, I'm willing to bet specialized buys their tubes from the same manufacturer.

[donevwil]

Does the valve hole on the inside of the rim have a burr, is the edge sharp and not covered by the rim tape ? I always deburr/blend a new rim's valve hole before taping, plus tubeless tape does a better job of protecting a valve in this area than most rim strips or tape.

[Ed-B]

I used to have this problem with press-on pump heads. Since I replaced the press-on heads with lever closure type heads I haven't had a tube fail at the valve stem.

Press-on pump heads put a lot of stress on the tube/stem interface.

Ed

[oldpotatoe]

Powder your tubes and don't use the valve nut. Maybe put a little extra rim strip at valve hole. Buy better tubes...:):eek:

[Hindmost]

Press-on pump head and a tube with threaded stem will result in what you are describing. Repeated pump head on and off weakens the tube at the valve hole.

After experiencing a few of these myself, I switched to tubes with non-threaded stems.

[cmbicycles]

All the stems are unthreaded, valve hole is smooth & covered. I only use the valve nuts for rack or water bottle spacers...;)

I've done literally thousands of tubes but never run into this with any frequency. I don't jam the adapter onto the stem, just over the threaded end... which all tubes have regardless of the rest of the stem. It happens when I use a floor pump or the compressor... though I use the floor pump a lot more. Maybe my tubes are just old... it looks like they just weren't glued well, half the valve is still hanging onto the tube and won't budge when I tug it (w/o some force, but even the bit pulls off some rubber) but half looks like it was never attached, clean separation.

Does Rapha sell tubes? Tubes are probably virtually all made by the same guys (kenda/cst/etc) with a few exceptions I'm sure.

[Ronsonic]

I had a plague of valve stem tears some years ago. I got this shiny new wheel and only had this sad old tire on hand that had somewhat dried out around the bead. The combination let the tire slip just enough to do the damage. Just to be able to ride it, I ran a bit of tubular cement around the bead, let it dry overnight and then put it all back together. No more problems with stems.

[Peter P.]

I had this happen with unusual frequency in the last year or two.

I'm beginning to suspect manufacturers are deliberately under-building tubes realizing we'll accept a certain number of failures without complaining. Increased profits.

Handlebar tape seems to have a shorter lifespan, too.