We asked Wheel Works in Garden Grove, California (714/530-6681) to fill us in on the details. Although a spokesperson was reluctant to specify the exact ingredients, we learned that the sealant (which is applied over the inside of the spoke nipples in a two-part process) takes about 12 hours to set up. It is impervious to the stresses and chemicals normally encountered in motorcycle applications. After you discard the tube, the total weight of the wheel is actually lower than with a tube. The reduced weight and the elimination of friction means that the tire runs cooler than with an inner tube. Wheel Works charges $59 per wheel to convert your wire wheel for tubeless use. This fee also includes the installation of a tire valve stem.