Bicycle Mechanics - tubes

This year, I have ruined 2 tubes.

The tubes were not puctured, but the part where the rubber joins the valve had stripped. Not all the way but just 1mm. Air would slowly go out, but if I tilt the valve at a certain angle then.. POOF.. all the air is out in a second or two..

So my question is, what causes this. I have never had a flat from punctures.. Only had pinch flats and these happening.. Is there any way to prevent this? What am I doing wrong?

Next question: can these tubes be patched, or should I just throw them away? If its patch-able, how?

Thanks.. dex

If they are presta valve, you might be snugging up the nut to much. Otherwise it can be a rim that is kind of sharp right at the hole, just file it smooth, or getting a little rough with the pump and yanking the stem around can do it. This is probably not the issue but running low pressure can let the tube "walk" around in the tire and cock the stem putting a lot of load on its base.

Also this is a not uncommon failure mode for tubes, if you don't find any of the
problems alluded to by the Rev. I lose about 10% of my tubes to this failure
mode. Might be a Monday morning tube from the Thailand factory. Steve

This year, I have ruined 2 tubes.

The tubes were not puctured, but the part where the rubber joins the valve had stripped. Not all the way but just 1mm. Air would slowly go out, but if I tilt the valve at a certain angle then.. POOF.. all the air is out in a second or two..

So my question is, what causes this. I have never had a flat from punctures.. Only had pinch flats and these happening.. Is there any way to prevent this? What am I doing wrong?

Next question: can these tubes be patched, or should I just throw them away? If its patch-able, how?

Thanks.. dex

I HAVE THE ANSWER :D

I had this problem for a while, and tried the obvious: smoothing out the valve hole, putting stacks of electrical tape around the hole -- then I actually used my brains......

I wrap a small strip of gaffa, about 6 or 7mm wide, right at the base of the valve (a few times around), BEFORE I PUT THE TUBE IN. You've obviously gotta make sure the gaffa is stuck/jammed right on the valve, and you need just enough so that it will act as a stopper. I've never had a problem since I started doing this, and I use Conti Supersonics (very light & thin: 55g) pumped up to 160psi in my 20mm Conti Gps. :) I suppose you could use other stuff; anything that will stop the valve pulling through -- but gaffa works fine.

The only 'con' is, if you have to take the tube off, you need to push it out with your tyre lever because some of the gaffa gets jammed in the hole, but it's not hard. I highly recommend this.

I'm pretty sure you can't fix the ones that have been damaged in the way you've described.

thanks guys!!!

I never ride w/ underinflated tires, well maybe in the 80~90psi region for a while (the gauge got crazy).

Anyway, I got myself two new spare tubes today.........

Thanks 531, I'll do that!!!

If you pump tubes with a hand pump, it's very easy to twist the valve and rip it off. A floor pump is better on that, and in terms of portable pump, it's one of the factors I like about the Topeak Road Morph.

Be careful when you remove the pump's head from the valve, especially with Presta. Pull it straight; don't twist it out, wiggle it out or bend it.

Regards,

If you pump tubes with a hand pump, it's very easy to twist the valve and rip it off. A floor pump is better on that, and in terms of portable pump, it's one of the factors I like about the Topeak Road Morph.

Be careful when you remove the pump's head from the valve, especially with Presta. Pull it straight; don't twist it out, wiggle it out or bend it.

Regards,

thanks mgagnonlv!

I had learned that lesson long ago... when I pulled the pump's head the valve came with it..... :D :D :D :D

Its just that I never had this problem(mentioned above) happen to me, until recently..

I only use my frame pump when necessary (flats, etc.), besides I could only pump it up to the 80s psi region :D. I use a compressor to pump up my tire to 120psi before I go out riding. ;)

I've had this kind of problem resulting from what the Rev alludes to. Each time I'd pump up the tire, it would force the stem out a little, and I'd snug the nut a little more. After several times, add a little stress like pulling off the pump head, and kablooey. Consequently, I quit using the little nuts. Far as I can tell, they accomplish nothing. (But then, I never put the caps on the stems, either. ;))

As far as I can tell, the only thing the nuts do is make it easier to get the pump head on valve stem when the tire is deflated. Once I tossed the nuts, I stopped having tubes fail at the valves.

Hey something I do to every rim thats stopped valve flats for me is to take a 3" peice of electrical tape, put it over the valve hole, and then push a pencil or screwdriver through the valve hole in the rim, from the inside out. This covers up the edges of the valve hole very nicely.

Gaffa?

I had to look it uo also.

"Hey, if you've never heard of this invaluable aid its basically a (usually black) cloth tape. Its damn sticky, super wide and you can rip it rather than having to cut it. Frankly its ace!"

Gaffer tape used in tv and movie production

Velox rim tape should protect your tube.

Gaffa?
It's also called "100mile per hour" tape because racing car drivers will use it to tape any loose panel work to the car during a race. The Mafia also use it to stop kidnap victims from yelling. :D

CHEERS.

Mark

Gaffa?

Sorry, I don't what you call it in the USA. I did a quick Google search on "gaffa tape" before my earlier post, and several US web pages popped up, so I assumed it was widely known.

It's that black stuff (well, usually black) that musician's 'roadies' use to stick down speaker cables, etc

This year, I have ruined 2 tubes.

The tubes were not puctured, but the part where the rubber joins the valve had stripped. Not all the way but just 1mm. Air would slowly go out, but if I tilt the valve at a certain angle then.. POOF.. all the air is out in a second or two..

So my question is, what causes this. I have never had a flat from punctures.. Only had pinch flats and these happening.. Is there any way to prevent this? What am I doing wrong?

Next question: can these tubes be patched, or should I just throw them away? If its patch-able, how?

Thanks.. dex
Hope this adds some light, when I first started using my new foot pump because, the fitting that went onto the presta valve was verey, tight. When remouvinig it from the vavle, cut the tube into the valve hole. Solution/ fitting long valve tubes, and holding the valve neck with pointy pliers against the nut whilst remouving pump fitting.

Sorry, I don't what you call it in the USA. I did a quick Google search on "gaffa tape" before my earlier post, and several US web pages popped up, so I assumed it was widely known.

It's that black stuff (well, usually black) that musician's 'roadies' use to stick down speaker cables, etc AHA, I'll bet it's slang for "gaffer's tape"; I've seen it used both for ad hoc motor racing body repair and securing cables, etc. from being trip hazards. Most of the music shows I attend are lowbrow enough that they usually use plain-old duct tape, its low-rent cousin.

Ya think duct tape would work for the purpose at hand?

Ya think duct tape would work for the purpose at hand?

I'm sure duct tape would work as long as it's sticky enough. The good thing about gaffa is that it's super sticky, so there's no way it will come off the valve , and it's reasonably easy to tear by hand. I just buy the cheaper, smaller version from the supermarket. The 'pro' stuff costs about $13 US a role. I found the plastic electrical tape to be not sticky enough.

This is what confused me: here's an Australian web site advertising "U.S. Gaffa Tape". Hence, I thought it was a common term.

http://www.bmusic.com.au/prod56.htm