Wheel Collider: Understanding scale

I am trying to make super simple vehicles with two wheels each like a steam roller or flintstones style car. The Wheel colliders seem to be flat circles rather than cylinders. What properties do I update to adjust this? If it is the transform scale, should the green outline of the collider show the width of the cylinder?

 

From my experiments with them, I'm guessing that the implementation of wheel colliders is based on downwards raycasts - there's not a physical disc/cylinder collider there. (To simulate a wider wheel with larger contact area, you'd mess with the sliding/friction value)

So they won't work for open-wheel vehicles - If the exposed wheel hits something that isn't fairly flat, bad things happen - only the cube 'body' in this test is actually behaving like a solid object:



(It's probably possible to combine a wheel collider with real colliders on/around the wheels to avoid this case. But if you want something like a monster truck that can climb over very rough terrain+obstacles, the standard wheel collider probably isn't an option)

 

Try add Mesh collider + convex to the wheels and add physics meterial "Ice" and test again.

 

Thank you!