Arthur Peabody

The rear tube was flat. The puncture was part of a noticeable edge that coincided with the end of a tire liner. I've been using liners for 30 years, never had this result; it was a liner I've used for years. I now suspect that both my tire gauge (a small Campbell-Hausfeld, digital, about the size of a finger, perhaps 20 years old.) and the gauge on my pump read low, judging from the effort I have to apply to pump in the next bit of air and how little difference it makes.

Iride01 

Just a puncture and not a small cut?

If the pressure was low enough you might have gotten a pinch flat with just one small cut instead of the traditional snakebite with two small cuts. Tire liner may or may not be a factor. But it might have helped to work against you this time.

Andrew R Stewart 

If by tire liner the OP means the usually plastic strips that fit between the tube and tire then yes, thee strip's ends can and do cause abrasion on the tube and sometimes enough to become a flat. My fellow mechanics, and I, have agreed that too low an air pressure will cause this abrasion to be worse.

I've not worked in the Western states where thorns and Goat Heads are a big issue but here in the NE USA we find belted tires work as well as ones with a tire liner, WRT penetration flats, but ride nicer. Andy

veganbikes

Yes those liners can easily puncture and abrade tubes they are excellent at that. If I needed to put stuff between tube and tire I would look at Tannus Armour it is nice foam and is going to have a really tough time abrading a tube and puncturing and will actually provide useful protection.

Generally I stick with good puncture protectant tires and regular proper inflation and don't worry too much but on my rear Rohloff wheel I did put in the Tannus in because changing a flat on that with the belt drive and such is a bit more of a pain so avoiding flats is helpful.

grumpus

I've seen this a few times.I think low pressure is more likely the cause - run at high pressure the tyre, liner and tube are clamped together, while at lower pressure there's more chance that they move relative to each other. Some tyre liners have feathered ends to reduce the chance of it happening, if yours doesn't you could thin the ends with a sander.

Arthur Peabody

A small cut and an indentation in the tube for the whole width of the liner. I've never seen that before.

Eyes Roll

Could possibly be a pinch flat. Were you massaging the tire from the outside whenever you are replacing the new tube or working on the old tube, before pumping the air into the tube, to ensure the tube was not falling between the tire and the rim.

Pictures say a lot more than words. Please post the pictures of the tube/puncture and the tire liner so we get a better idea. Thanks.

Hvac

I recently had a squeak front in tire. Ultimate cause was rub between rim strip and tube. Took this oldster a few times to finally see the defect in the rim strip. Over time I suppose it could have punctured.