What is the name of the race series central to Pixar's Cars?

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

Lightning McQueen is a rookie competitor chasing the Piston Cup championship in the film. The story begins after a three-way tie between McQueen, Chick Hicks, and Strip Weathers, known as The King, forces a final race in California to decide the winner.

The fictional competition is modeled on American stock-car racing, particularly NASCAR. Cars uses familiar racing details such as pit crews, sponsors, speedways, qualifying, and championship points while creating its own vehicle characters and sporting history.

The Piston Cup name also appears throughout the sequels and franchise merchandise. It should not be confused with the World Grand Prix in Cars 2, which is an international racing event, or the Dinoco sponsorship associated with The King and later Lightning McQueen.