NASCAR K&N Pro Series driver and U.S. Navy Lt. Jesse Iwuji describes the science behind the different substances used in NASCAR tires at the Daytona International Speedway July 1, 2016. Members of the 45th Space Wing and other military units toured Sprint Series Cup and Xfinity garages before the start of the Subway Firecracker 250 race. (U.S. Air Force photo by 1st Lt. Alicia Premo/Released)