Getting a repeat puncture, in the same place, on my pompino and it’s starting to do ma swede in. Must have had it 5 or 6 times now, but it’s sporadic, like over the course of a year. It’s right by the valve stem:

[below the circular valve piece and just to the left of the main seam in that photo]

Changed the tyre and re-taped the rim to no effect. It seems like it must be something to do with the tube getting pinched in the valve hole? Any ideas on causes / fixes?

Another thing is that it never happens on a ride, it’s always on returning to the bike when it’s parked up.

The tyre slipping on the rim? That is about the only thing I can think that could cause that.

Are you a bit over aggressive with locknuts?

Have seen that a twice with two separate customers , both had repeated flats just like that
In both case we put a nice velox rim tape on and it fixed there issues

Thks for the suggestions. I re-taped it with velox cloth tape, as it goes, and it looks fine just eyeballing the rim.
I don’t use locknuts – might that be the problem? Bit of unwanted movement around the valve stem or somesuch.

What do you mean by the tyre slipping George – like it moves a bit round the rim and causes some sort of compression-type puncture?

what sort of pump are you using, if your locking onto the valve you can rock it back and forth

Press your finger in the place on the rim with a pressure of 100psi, does it hurt?

My guess is there’s some metal sticking up somewhere. Might be worth stripping the tape out and doing a very careful and gentle feel around with your little finger. Even if you can’t feel anything, try a bit of sand paper in the general area and in the hole.

edit: I never use locknuts either, I don’t think it’s that.

What do you mean by the tyre slipping George – like it moves a bit round the rim and causes some sort of compression-type puncture?

Something along those lines yes. Either compression or stretching the tube.

I used to get punctures on the turbo trainer.

Turned out to be the rim tape, or electrical tape to be precise 🙂

Yeah, if you get a slit in the rim tape it might not be visible without very close inspection. But at high pressures, the tube can ‘herniate’ through and go pop. Confused the hell out of my for ages, because the rim tape looked absolutely fine.