Recurrent flats
 

I'm having the wierdest problem with the 20" rear wheel on my BikeE AT.
I got a flat tire, and when I examined the tube the cut (like a snake bite)
was on the inside, toward the rim, rather than on the outside where the tire meets the road. I checked the rim for any protrusions or sharpness and could find nothing. Everytime I put a new tube in, it blows out in exactly the same place in very short order. I know I'm missing something obvious here. I've replaced dozens of tubes in my lifetime, so I'm pretty sure I know how to do it correctly. I've been through 3 tubes today. Any ideas?

Inspect the rim tape, even the slightest edge of an exposed spoke hole will cause a puncture when air pressure pushes the tube against the rim

- or -

Check the tire bead, I once had a reinforcing wire protuding through the casing on the bead that cased repeated flats.

Yup- it was a small tear in the tire right against the rim. Thanks for the help,Threadend. Sometimes we
have to put it down and pick it up another day. Or maybe stronger bifocals...?