C# Unity suspension example script for wheel meshes to follow wheel collider suspensions

Wheel.cs

using UnityEngine;
using System.Collections;

// ADD THIS SCRIPT TO EACH OF THE WHEEL MESHES / WHEEL MESH CONTAINER OBJECTS
public class Wheel : MonoBehaviour {

  public WheelCollider wheelC;

  private Vector3 wheelCCenter;
  private RaycastHit hit;

  // Initialization
  void Start () {

  }

  // Display
  void Update () {
    wheelCCenter = wheelC.transform.TransformPoint(wheelC.center);

    if ( Physics.Raycast(wheelCCenter, -wheelC.transform.up, out hit, wheelC.suspensionDistance + wheelC.radius) ) {
      transform.position = hit.point + (wheelC.transform.up * wheelC.radius);
    } else {
      transform.position = wheelCCenter - (wheelC.transform.up * wheelC.suspensionDistance);
    }
  }

  // Physics
  void FixedUpdate() {

  }
}