The Indianapolis 500 auto race was won in 1911 by a car running Firestone tires, as did all winners of the race from 1920 to 1966. The company also provided tires to Formula One from 1950 to 1974. Citing rising costs as the cause, Firestone announced its withdrawal from professional motorsport in August 1974 with the exception of Formula 5000 and Formula One. The change was forecast to reduce Firestone's annual race testing budget from between $6 and $8 million to around $500,000 (in , roughly equivalent to a reduction from $–$ to $.) Shortly afterward, Firestone extended this to a complete withdrawal by the end of the 1974 season. The manufacturer returned in 1995 to the CART series with technical assistance from Bridgestone. Goodyear retired after 1999, thereby leaving Firestone as the single tire supplier for the IndyCar Series as of 2021.