'Phantom' punctures

[qpw]

For the second time in around 20 years of cycling I have just had a 'phantom' puncture.

What happened, in each case, was that I would use the bike one day and everything would be fine. The next day I would go to use it and it would one of the tyres would be completely flat.

So I'd take off the wheel, slightly inflate, check for a leak and find nothing. Remove tube, place in water - again, nothing.

In the first case, not having a spare tube, I put the original back on the bike, inflated it, and it remained fully inflated indefinitely.

In the latest case, the tube has been sitting, gently inflated, and not losing any air, for several days.

In both cases the presta valve was screwed down and the valve cap was on. Also, in both cases, there was no chance that anyone had access to the bike to play a 'joke'.

I'm completely at a loss as to how this could happen and would welcome any theories.

 

[Tim Hall]

Some presta valves (Specialized tubes do this I think) have removable cores. They can leak. My remedy has been to unscrew the core with a pair of pliers, put a twist of PTFE tape on the thread and replace, doing it up tight.

Of course if your tube doesn't have a removable core it must be down to another cause, like eddies in the space time continuum.

 

[Biker Joe]

Supernatural pranksters

 

[Andrew_Culture]

I've had a couple in the last few months and if they go down a second time I replace them. I usually repair tubes but prefer reliability over the sense of victory that fixing a phantom puncture gives.

 

[Biker Joe]

I've had a couple in the last few months and if they go down a second time I replace them. I usually repair tubes but prefer reliability over the sense of victory that fixing a phantom puncture gives.

No sense of adventure

 

[PK99]

Some presta valves (Specialized tubes do this I think) have removable cores. They can leak..

I've had that problem!

 

[Andrew_Culture]

No sense of adventure

My last few commutes indicate otherwise

 

[fossyant]

Most likely valve core. Remove, put a dab of oil on it, and refit.

 

[youngoldbloke]

I have had tubes (Continental) with mysterious phantom punctures which turned out to be caused by a fault at the base of the valve where it joins the tube. All was fine until the valve was disturbed even slightly. Try putting the valve area of the inflated tube under water and pushing the valve from side to side.

 

[accountantpete]

Valve and something to do with the temperature.

 

[PK99]

I have had tubes (Continental) with mysterious phantom punctures which turned out to be caused by a fault at the base of the valve where it joins the tube. All was fine until the valve was disturbed even slightly. Try putting the valve area of the inflated tube under water and pushing the valve from side to side.

Often resulting from under inflation esp on Mtb tyres. Every bump pushes the tyre round a smidgin and eventually puts stress on the base of the valve stem. Regular check that valve stem is at 90 degrees to the rim avoids the problem. Problem exacerbated if stem hole in rim has sharp edges.

 

[lulubel]

I have had tubes (Continental) with mysterious phantom punctures which turned out to be caused by a fault at the base of the valve where it joins the tube. All was fine until the valve was disturbed even slightly. Try putting the valve area of the inflated tube under water and pushing the valve from side to side.

I think there was a faulty batch of Conti tubes at Wiggle (and probably other stores) about 2 years ago. I had this repeatedly with the tubes from a particular order (road tubes, inflated to 100-110psi). Once I'd got through those, I didn't have the problem with the next lot.

Also, I find Conti tubes often come with loose valve cores.

 

[youngoldbloke]

I think there was a faulty batch of Conti tubes at Wiggle (and probably other stores) about 2 years ago. I had this repeatedly with the tubes from a particular order (road tubes, inflated to 100-110psi). Once I'd got through those, I didn't have the problem with the next lot.

Also, I find Conti tubes often come with loose valve cores.

Maybe that was the problem - road bike, 100-110psi too. I now prefer Michelin Airstop - prefer the unthreaded valve stem.

 

[byegad]

You got th admire the ingenuity of the, never to be named, fairey don't you?