The NTT Indycar Series is going even more green than usual! No, this time we are not talking about green flag starts or more races in the calendar. The last race at Nashville, the Big Machine Music City Grand Prix, saw the official debut of a new tyre compound provided by Firestone, announced priorly by the chairman of Penske Entertainment back at the end of April. Tested during the Carb Day pit stop challenge for the Indianapolis 500, this race tire has a new sustainable compound built with eco-friendly natural rubber, produced from guayule shrub, a plant that grows up more commonly in the south-west states of the US and in Mexico especially. Cara Krystolic, Firestone's and Bridgestone's director of race tire engineering and production, announced that this long-term project developed at Bridgestone's experimental farm in Arizona, had a massive investment of over $100 milion throughout the last 10 years. Nashville's race has been a successful test for the new compound, as Firesto...