Rigidbody problem (423835)

i’ve crated a little car and apllied a rigidbody.
When i change the mass of rigidbody,the mass is not calculated,my car result very light car and when i steer they fly!
i’ve changed mass of the rigidbody,but no any change in physics.
i try to set it from 0 to 10000 but not change.
can help me?
i’m using unity 3 pro.
sorry for my english.

Hi-- We are likely going to need more info to help you out on that one-- any screen shots of the inspector would be helpful.

the whells collider is setted via script.