Call this function to set this wheel's suspension damping constant. This controls the resistance to movement of the wheel's suspension. The suspension force is calculated by a method similar to the one below: 
    float CalculateSuspensionForce(
        const Wheel& wheel, 
        float fSuspensionCompressionDistance,
        float fSuspensionMovementSpeed)
    {
        float fSuspensionForce = 
            wheel.fSuspensionSpringConstant * fSuspensionCompressionDistance + 
            wheel.fSuspensionDampingConstant * fSuspensionMovementSpeed;
        return fSuspensionForce;
    }
  The default value is 9000.0f.