The metric four-link suspension has two links above the rearend and two links below the rearend. They are angled from a top view to prevent the rearend from moving side to side as the chassis rolls. With this system, the rearend stays located by virtue of the opposing angles of the upper and lower links. The roll center in this system is very high compared to other systems. To get the rear to roll, teams use a much softer right rear spring than the left rear. Using a stiff right rear spring will cause the car to be very loose.