Originally Posted by
Null66
I once had the weirdest (too me) bur on the inside of the wheel it barely poked through the rim tape when wheel was disassembled.
I only found it as I was running finger along each surface and it gave me a rather nice slice. Pulled off rim tape and there were a couple burs where the spoke holes were drilled. Sanded them smooth. Some nice new tape and no more flats!
About the same thing here, only it was an infinitesimal piece of wire from the brakes in the rear. Had a flat, needed a tuneup (which was free for life from my LBS for buying it there) so I had them change it. All I can figure is that he snipped off the excess rear brake cable that was frayed BEFORE he changed the tire and a tiny piece fell down between the tire and tube. Had 2 tubes with low leaks until I fond it with my fingers. I could only see it with a magnifying lens when I found it and had to pull it with tweezers. It is astounding that it can be a foreign object that is so small and cause a leak. I like the cotton ball idea too, I'll have to try it the next flat I get.
I had a series of 3 bad tubes on my newest bike. All blew out where the stem is joined to the body, all appeared to NOT puncture in the traditional sense but the rubber skirt surrounding the valve came unfastened from the body, must of been insufficient vulcanization. These were all puncture resistant tubes too - fat lot of good that did.