Increment Car Rotation along with steering Wheel

I am trying to build a car simulator in steam VR, I want the car and wheel to rotate by 30 degrees when I rotate the steering by 360, The problem I am facing is when I rotate the steering the 2nd time the car resets back to its original rotation angle that is at 0 to 30 degree again. How can I increment the angles. Below is the code that I tried to increment the angles but it not workingas the posFinal and posInitial are only varying from -0.4 to 0.4.

using System.Collections; using System.Collections.Generic; using UnityEngine; using Valve.VR.InteractionSystem; [RequireComponent(typeof(Interactable))] public class RotateWheel : MonoBehaviour {

 public Transform Steer;
 
 public Transform Wheel2;
 public Transform car;
   
 float scalingFactor = 0.5f;
 

public float posInitial; public float posFinal; float temp;

 void Start()
 {
     posInitial = 0f;
     posFinal = Steer.transform.rotation.y;
   
     car.transform.eulerAngles = new Vector3(0, 0, 0);
    Wheel2.transform.eulerAngles=new Vector3(0,0,0);

 }

  
 private void FixedUpdate()
 {
         Wheel2.transform.eulerAngles = new Vector3(-0, ((car.transform.eulerAngles.y+(posFinal-posInitial) )*30f/360), 0);
         car.transform.rotation = Quaternion.Slerp(Wheel2.transform.rotation, Quaternion.identity, (Time.deltaTime *5) / scalingFactor);
         temp = posInitial;
         posInitial = posFinal;
         posFinal = Steer.transform.rotation.y;
     }