Cyclists Beware! Nylon Rim Liner Causing Flat Tires (Video)

I had this weird problem over the summer when I was mysteriously getting consecutive flats for a week straight in my rear wheel for no explained reason.  I first believed it to be defective tubes, but upon closer investigation, it turned out that the rim liners (which are supposed to prevent interior punctures) were actually causing the flats.

The reason this was only happening in the rear wheel was because the rim contour caused the liner to get stuck in this U-shaped position with the edges pointing up toward the tube.  After being on the bike for so long, being stretched, and all crusty from the heat, the rim liner was sharp enough to slice the tube.  The front rim was a double walled design, which allows the liner to sit flat with no edges pointing upwards.  I have since bought a new rear wheel which is double walled, so I shouldn't have this problem in the future.

Solution: get wider rim liner, don't use nylon rim liners or get double walled rims.