Unexplained punctures

[byegad]

I had a series of front and rear flats, sometimes expolsive other times slower. The cause was deep section aero rims, so deep the valve reinforcement was sitting proud of the inner rim profile allowing the tube to over stretch as it tried to fill the gap. Solution was easy if expensive. a new pair of wheels and no more punctures!

 

[jimbut]

It is fairly easy to overtighten the valve rim retaining screw putting excessive pressure round the valve welt which can then develop small splits. I know cos I`ve done this ( twice ) before an experienced cyclist advised me of the error of my ways.

 

[yenrod]

What causes them? - assuming you have ruled out the obvious culprits on a 700x23 tyre: e.g.

(1) external and internal penetrating objects
(2) snagged tubes
(3) under-/over-inflation
(4) poorly positioned brake block rubbing on the tyre
(5) inferior quality tubes or tubes that are too thin

What have I missed? Any unusual experiences?

Bits of wire (from a cable) in the tyre that you cant see