Causes of mystery punctures?

[graham bowers]

I don't get may punctures, but of those I do, I only find the culprit in about half of them - thorns, flints, glass usually. But the others, I find nothing - the tube is pricked, but nothing in the tyre.
I guess by definition its not possible to discover the cause.
Doed this happen to everybody???

 

[Milkfloat]

It used to, but now I mainly run tubeless.

 

[Salty seadog]

The physical cause of punctures is not always found. It could be a sharpie that penetrates the tyre but is not picked up or shed soon after, it could go right through and out the other side or even a pinch puncture where the rim causes the damage. There is also the possibility of cut up rim tame or spokes doing the damage. Just be thankful that you don't get many as you say.

 

[Alan O]

I don't get may punctures, but of those I do, I only find the culprit in about half of them - thorns, flints, glass usually. But the others, I find nothing - the tube is pricked, but nothing in the tyre.
I guess by definition its not possible to discover the cause.
Doed this happen to everybody???

Yeah, probably about 50/50 over the years.

 

[Smokin Joe]

Whatever penetrates the tyre is often forced back out as the air escapes.

 

[Globalti]

It only takes a tiny shard of glass embedded in the carcass to cause multiple mystery punctures.

 

[Dave7]

Not wishing to tempt fate but I have been very fortunate with the p*****e fairy. Only one in 5 years and that was on a Specialized I had for a days trial.
I do ensure my tyres are at 90......60 for the hardtail.

 

[alecstilleyedye]

tyre past it's sell-by date, as i found out yesterday. only got 8,000km out of it…

 

[mrandmrspoves]

A tip.particularly useful in Winter months when your fingers are cold and numb. Use a cotton wool ball to run around the inside of the tyre. The fibres will snag on even the smallest sharp object and should there be sonething more substantial lurking, you wont shred your fingers. If you happen to carry a first aid kit the cotton wool ball can be stored in there for dual function.

 

[Moodyman]

On the road bike I had 9 punctures on 7 rides. Never found anything in the tyre. Turned out rim tape. It moved off centre and allowed tube to get caught and pinched.

New rim tape. Sorted.

 

[andrew_s]

Sharp objects can lurk within the thickness of the tyre rubber and carcase, and only poking out slightly when the tyre is deformed as it passes the contact patch.

It doesn't have to poke out far enough to get through the tube, only far enough to put a slight nick in the surface of the tube.
The tube rubber then stretches away from the nick (assisted by tube squirm), and the air pressure inside then pushes the tube above the end of the nick downwards for the sharp to extend the depth of the nick.

A small fragment of glass, probably broken off the tip of a larger fragment, is most common, but I've also had such punctures from about 1 mm of a strand of wire. That was difficult to find!