Suspension Help

I have this script to create a car like suspension but the only problem is that it doesn't have a resting point like a real life Wheel suspension would have, is there anyway where i can stop it acting like a hover car type suspension and have it more like a car suspension? if anyone could help that would be amazing :)

using UnityEngine; using System.Collections;

public class testSuspension : MonoBehaviour {

 public float springStrength;
 public float springDistance;
 public Transform[] Springs;

 public Rigidbody rb;

 void Start() 
 {
     rb = GetComponent<Rigidbody>();
 }

 void FixedUpdate () 
 {
     RaycastHit hit;

     foreach (Transform Spring in Springs) 
     {
         Vector3 downwardForce;
         float distancePercentage;

         Debug.DrawRay(Spring.position, -Spring.up * springDistance  , Color.green);

         if (Physics.Raycast (Spring.position, Spring.up * -1, out hit, springDistance)) 
         {
             distancePercentage = 1 - (hit.distance / springDistance);

             downwardForce = transform.up * springStrength * distancePercentage;

             downwardForce = downwardForce * Time.deltaTime * rb.mass;

             rb.AddForceAtPosition (downwardForce, Spring.position);
         }
     }
 }

}