Car steering issue

I'm following this tutorial using this model. I've set up the front wheels to rotate across the Y axis so they look like they are steering. However, the Left Front "NSF" wheel isn't rotating where I'd like it to. It seems to be in line with the Front Right "OSF" and just moving backwards and forwards whilst rotating. Here is my code so far :

 pragma strict
 var wheelNSF : WheelCollider;
 var wheelNSR : WheelCollider;
 var wheelOSF : WheelCollider;
 var wheelOSR : WheelCollider;
 var maxTorque : float = 50;
 ;
 var wheelNSFTransform : Transform;
 var wheelNSRTransform : Transform;
 var wheelOSFTransform : Transform;
 var wheelOSRTransform : Transform;
 
 
 
 function Start () {
 rigidbody.centerOfMass.y = -0.9;
 }
 
 function FixedUpdate () {
 wheelOSR.motorTorque = maxTorque * Input.GetAxis("Vertical");
 wheelNSR.motorTorque = maxTorque * Input.GetAxis("Vertical");
 wheelOSF.steerAngle = 10 * Input.GetAxis("Horizontal");
 wheelNSF.steerAngle = 10 * Input.GetAxis("Horizontal");
 }
 
 function Update(){
 wheelNSFTransform.Rotate(wheelNSF.rpm/60*360*Time.deltaTime,0,0);
 wheelNSRTransform.Rotate(wheelNSR.rpm/60*360*Time.deltaTime,0,0);
 wheelOSFTransform.Rotate(wheelOSF.rpm/60*360*Time.deltaTime,0,0);
 wheelOSRTransform.Rotate(wheelOSR.rpm/60*360*Time.deltaTime,0,0);
 wheelOSFTransform.localEulerAngles.y = wheelOSF.steerAngle - wheelOSFTransform.localEulerAngles.z;
 
 wheelNSFTransform.localEulerAngles.y = wheelNSF.steerAngle - wheelNSFTransform.localEulerAngles.z;
 }

Is it a model issue? Or am I coding incorrect?