 The IndyCar Series runs the bespoke compounds since 1996 and re-profiled in 2003.The front tire sizes are 305/45-R15 (10.0/25.8-R15) and the rear tire sizes are 415/40-R15 (14.5/28.0-R15).The compounds and construction of IndyCar Series tires unique to each mounting position on the race car.