The sideboards on a Sprint Car wing can obstruct the oncoming air when the car is traveling at an angle to the direction of travel. This sideways slide reduces the efficiency of the wing and also moves the center of force forward. Attempts are made to reduce this effect by lowering the right side panel, but it still sticks up 4-6 inches or more. That is enough to disturb the airflow and reduce what little downforce exists. This chart shows the area that is affected by the sideboard. Remember that both sides of the wing are affected by the board, so lowering the right side board only helps with the "flat panel' downforce, not wing-induced downforce because the underside is important also and is highly obstructed by the side panel.