I have discovered a Law of Conservation of Flats. Flats can neither be created nor destroyed, but may change into some other form of flat. Example -- since going to Marathon Plus with Mr. Tuffy tire liners, I have cycled about 25,000 flat-free miles. However, my car has gotten several flats during this period. Prior to fitting these tires, I had gone for decades without a car flat. Clearly, the bike flats, far from being eliminated, had changed into car flats.

Paul