The late 1970s saw the introduction of the “ground-effects” aerodynamic design incorporated in various Indy car chassis—introduced to the sport by Jim Hall’s Chaparral 2K. The ground-effect design incorporated moveable skirts under the vehicle to "seal" against the ground, creating a vacuum that increased vehicle handling and speed, especially in the corners. Team Penske's response to Hall’s breakthrough invention was the PC9 chassis, the first Penske chassis designed from the start using "ground-effects." Despite hours of pre-season testing, the PC9 the car was no match for Hall's Chaparral 2K, and in the 1980 Indianapolis 500, Mears led just nine laps. Late in the race, Mears was catching Tom Sneva for second place when he cut a tire and had to make an unscheduled pit stop for new tires, losing a lap. Mears had to save fuel late in the race as well, dropping him to a fifth-place finishing position. Throughout the season, Team Penske improved the PC9 chassis and became competitive against the Chaparral. Mears won the road course race in Mexico City in the PC9, his only win of the season.