Hello,
Maybe we should move this to the "Anything goes" section....heheh.
I'm totally with you on the cardboard cutouts. I've always understood the fact that a smaller diameter is going to turn more RPM's to make the same ground.
The difference between the cardboard and a tire is the fact that the card board is a solid circle, the circumference clearly changes when you change the diameter. When changing the diameter, (or radius if you want,) you are adding or taking away material from the true circle. Therefore changing the Diameter, and the Circumference. With a tire, the tread remains the same, leaving the circumference the same as when it's full of air. Now, I can understand how changing one tire will be noticed by the ABS system, because of the other tires having lost tread, (material missing) the circumference is different.
Let's say a tire has a circumference of 24". with 5lbs, or 35lbs, the circumference remains constant. While the radius changes, it shouldn't have an affect on the revolutions, seeing how the circumference remains the same, so should the RPM's. With something like cardboard, when you change the radius, you change the circumference, therefore, changing the RPM's.
Man...I haven't typed this much since WebTV.
Later now,
Clint