Algodoo

Demonstrates "soft" tire behavior. Also shows how radially arrayed, hinge attached objects can provide rotational damping.

Something to note is that the circles that act as the base for the wheels collide with nothing. This allows the hinge attached knobs to absorb the brunt of large impacts, which results in less energy being passed on to the suspension, which results in a smoother ride and fewer catastrophic suspension failures.

Concerning the rotational damping...

This seems to be a side effect of the way Phun implements hinges. The rotational damping occurs whether air friction is on or off, so I believe it is caused by the stretching of the hinges. At high speeds, the hinges are stretched, which presumably exerts a force between the two objects being hinged. This force pulls the two objects back toward each other, but due to rotational forces they maintain a separation. This constant force apparently slows down rotation.

As far as I can tell, it is logarithmic or exponential, so that slow rotation results in little damping, while fast rotation experiences significant damping.

I have utilized this property to create the "engine", which serves to counteract the torque put out by the rear wheel and helps keep the front end on the ground.

Forward - d
Backward - a
Brakes - s