What championship race series is central to Pixar's Cars?

The Piston Cup is the championship race series central to Pixar's Cars.

Lightning McQueen competes in the Piston Cup during the first film, where a three-way tie leads to a final race involving Lightning, Chick Hicks, and The King. The competition gives the story its initial goal and establishes Lightning as a talented but self-centered rookie.

The series is a fictionalized version of American stock-car racing. Its name evokes an engine component while also sounding like the names of real motorsport championships. Dinoco is the prominent sponsor associated with The King and later becomes an important symbol of racing prestige.

Cars 2 shifts attention to the World Grand Prix, an international event with different competitors and locations. That change means the Piston Cup is most strongly associated with the first Cars film and Lightning's original racing career.