NASCAR side skirt and sway bar rules change

NASCAR has increased the ground clearance of the side skirts on Sprint Cup cars again in hopes of improving the aerodynamics of the cars.

The minimum clearance between the ground and the bottom of the body of the side panels (called the side skirts because they are extensions of the side panels) will be 4.5 inches on the right side and 5 inches on the left side, according to a NASCAR technical bulletin issued Wednesday.

At the start of the year, the clearance was 3 inches on each side. Last month, NASCAR increased the clearance by an inch on the right side of the car and 1.5 inches on the left.

The changes, which go into effect with the race next week at 1.5-mile Kentucky Speedway, are designed to decrease side downforce and increase the ability of drivers to race side-by-side.

NASCAR Sprint Cup Series teams received a technical bulletin today (6/20), outlining the following rule changes effective 6/27:

  • Ground clearance for all side skirts has been increased by ½ inch. Right side skirts must have a minimum clearance of 4.5 inches/maximum clearance of 5 inches. Left side skirts must have a minimum clearance of 5 inches/maximum clearance of 5.5 inches. This is the next step in looking at the aero package for intermediate race tracks.
  • Both the right and left side rear sway bar arm connecting links must be perpendicular to the ground from all viewing angles when car is at ride height. This is an effort to maintain consistency in rear sway bar setups. NASCAR