Originally Posted by
Schwinnsta
The picture of the contact patch makes no sense to me. I would have assumed that the area of the patches shown should be the same. The weight of the rider of rider and bike being the same in the three tires and it is equal to the area of the patch times the air pressure. I'm confused.
I suspect the narrow tyre suffered such a severe collapse that the sidewall deformed, also the contact patch, rendering the pure physics equation an approximation. The equation would be valid if the tyre is modelled as a pure elastic medium. Which for a soft narrow tyre it clearly is not.