Lightning McQueen keeps Rust-eze as his sponsor after turning down Dinoco in Pixar’s Cars.
Rust-eze initially sponsors McQueen, whose racing number is 95, and its medical-product branding is displayed prominently on his bodywork. McQueen dreams of replacing Rust-eze with the prestigious Dinoco team, but his experiences in Radiator Springs change his priorities.
At the Piston Cup finale, McQueen stops to help The King after Chick Hicks causes a crash. Although McQueen loses the race, Dinoco offers him a sponsorship opportunity. McQueen instead chooses to remain loyal to Rust-eze, and Tex Dinoco later rewards that decision by sponsoring Rust-eze as well.
This ending is sometimes misremembered as McQueen immediately becoming a Dinoco racer. Dinoco becomes an important connection for the characters, but McQueen’s visible racing partnership remains tied to Rust-eze at the film’s conclusion.