title: Wheel Collider Unity: after adding torque the vehicle starts moving sideways
body: <p>I really killed few hours to try to fix this, Googling for a solution, but I could not.</p>
  
  <p>I've got a vehicle, it's a go-cart, so there are no suspensions (technically there are, but the values are close to 0, to simulate the tires). The vehicle has a rigid body attached and the child object contains the 4 wheel colliders (and the model itself), as can be seen here:</p>
  
  <p><a href="https://dl.dropboxusercontent.com/u/76599014/sxc/Clipboard01.jpg" rel="nofollow noreferrer">https://dl.dropboxusercontent.com/u/76599014/sxc/Clipboard01.jpg</a></p>
  
  <p>For testing, I added a short script to make the vehicle move. It's in the GameObject called "gokart":</p>
  
  <pre><code>public class carControler : MonoBehaviour {
  
  public WheelCollider fr, fl, rr, rl;
  public float performance = 50f;
  
  void FixedUpdate () {
      throttle();
  }
  
  public void throttle() {
  
      this.rl.motorTorque = this.performance;
      this.rr.motorTorque = this.performance;
  } }
  </code></pre>
  
  <p><strong>What happens is</strong>: the rear <strong>wheels</strong> start to <strong>rotate</strong>, as intended, but the <strong>vehicle starts moving sideways slowly</strong>. The movement speed depends on the torque amount (the wheel rotation in this case). There is <strong>no movement forward</strong>, so this is not the bug, where when you are standing on a flat surface you are drifting on the sides.</p>
  
  <p>Any ideas? If you need a video or a GIF (I have to figure out how to make one) of the movement, I'll be glad to provide one.</p>