private void ApplyForces()
        {
            if (tiresOnGround > 0 || airTime < 0.3f)
            {
                //stop sliding sideways//
                physicsRigidbody.AddForce(physicsBody.transform.right * WheelVelocity.x * -(tireGrip * 140f) *
                                          Time.fixedDeltaTime);

                //downforce//
                if (downForce > 0)
                    physicsRigidbody.AddForce(Vector3.down *
                                              (Mathf.Abs(WheelVelocity.z) * downForce * 0.1f *
                                               physicsRigidbody.velocity.magnitude) * Time.fixedDeltaTime);
            }
            else
            {
                if (airTime > 0.3f)
                {
                    //increase gravity//
                    physicsRigidbody.AddForce((Physics.gravity * physicsRigidbody.mass) * 2f);
                }
            }
        }