Just read "Flat Free Tires" in Countryside Mag, Vol 94, No 4. These tires (by Marathon, Carefree Tires, andTricam) are made of light polyurethane and are easy to change. They will save lots of energy that the average tire might require of you being patched.
If you try to please everybody, your progress is limited by the noisiest fool. And this tiny ad: