[Dick Linn]

We may use pneumatic tires, but if we do use the polyurethane tires, I will simply use a rough-tooth, round "rat-tail" wood file of the same diameter as the partial grooves in the tread ( maybe 5/16 ?) and file a groove in the center raised portion. It connects much better with the mesh. I filed a couple of grooves and just did a drag test on the sample piece of mesh and the difference was amazing. I don't know how well the poly tire will hold up to this abuse, but you can always resharpen the edges of the groove periodically by cutting a fresh edge with a razor blade. Many motorcycle racers do this (or used to) to keep a sharp edge and reduce tire replacement costs. Just make sure you do not make the groove so deep that it protrudes below the surface of the mesh - see the rules on that one.