Wheel Collider - Mesh/Box Collider Problem

Hey everyone!

I'm trying to implement a simple car application. I am using the scripts from Unity car tutorial (same scripts, same meshes). But as soon as i add the box or mesh collider to my car game object, car starts to rotate like crazy! It's just same as the tutorial. What may be causing this problem? Am I missing som physics settings (I checked them a hundred times, they are same)

Thank you!