Objects start to fly after adding wheel colliders

Hi, I have a problem with the collider, When i add wheel collider to wheel object, and hit play, the car will fly and rotate around itself after hit the terrain, i add or change nothing from default setting and wondering why this happen I added rigidbody to car body and a gameobject as child with box collider component, its fine till add collider to wheels, anybody can guide me on this issue?

Try setting the rigidbody’s mass to something reaistic (~1000 Kg)