Speed calculation (1 Viewer)

[Marn0]

And really, the "height" of the tire is 2x the lower radius, measured from the center of the axle to the ground. There's a flat spot on the bottom. Nit-picky, but true. Tires are "smaller" if they have less pressure or more load on them.

The height of the Tyre may change with pressure, BUT the rolling circumference stays the same so therefore the Tyre only looks smaller but will still spin at the same speed.

 

[Fast Eddy]

The height of the Tyre may change with pressure, BUT the rolling circumference stays the same so therefore the Tyre only looks smaller but will still spin at the same speed.

This is not true and I can easily prove it with an example. Lower the pressure to zero and measure the axle-to-ground distance, the effective radius of the tire/wheel. It is certainly lower than it would be at 20psi. The distance traveled per revolution of the tire is clearly relative to the pressure in the tire.

 

[Marn0]

This is not true and I can easily prove it with an example. Lower the pressure to zero and measure the axle-to-ground distance, the effective radius of the tire/wheel. It is certainly lower than it would be at 20psi. The distance traveled per revolution of the tire is clearly relative to the pressure in the tire.

yes the height of the tyre changes, but the rolling circumference does not. the same amount of tread still has to pass the contact patch on the ground unless it slips

 

[Fast Eddy]

unless it slips

It does. And folds, and wrinkles, etc. The weight easily overcomes the tire shape.