In the world of IndyCar racing, the track surface at Southern California’s exclusive Thermal Club has earned a notorious reputation as the ‘Coachella Valley Cheese Grater.’ Renowned for its tire-shredding sharp aggregate, this private road course stands unmatched in its capacity to wear down tires at an alarming rate. This weekend, the track sets the stage for its inaugural championship motor race, and the tire abrasion trend is set to persist.
In anticipation of Thermal’s punishing track surface, IndyCar is temporarily deviating from its recently adopted tire distribution policy. This policy, first implemented in St. Petersburg, provided teams with five sets of the softer, less durable alternate tires and five sets of the harder primary ones. However, in a strategic move to cater to Thermal’s demanding terrain, the allocation has been tweaked to six primary sets and four alternate sets, ensuring teams have a larger supply of the more durable tire compounds.
The call for changes in tire distribution was made by Cara Krstolic, Firestone’s chief engineer and director of race tire engineering and production, and her team. They responded to IndyCar’s request for a greater performance gap between its road racing compounds. The adjustments were put to the test in St. Petersburg, where the alternates, though fast, struggled to last more than a dozen laps. The stark contrast between the compounds was clear, and Firestone has made specific changes to adapt to Thermal’s aggressive 3.067-mile circuit.
Krstolic, speaking to RACER, revealed the discussions held with IndyCar during the off-season. The consensus was that the tires needed to generate more interest. To achieve this, efforts were directed towards creating a wider gap and ensuring the alternates wore out faster, instead of remaining effective over a full stint, which would not make for compelling racing.
For Thermal, a slightly different approach was adopted. Rather than striving to make the alternate tire softer, as was done on street courses, the focus was shifted towards increasing the durability and toughness of the primary tire. Krstolic explained that even last year at Thermal, there was significant drop-off, even with the primaries. The aim now is to make the primaries more robust and temperature-resistant, while still maintaining the difference with the alternates.
Last year’s non-points ‘All Star’ race at Thermal saw teams using harder Firestone compounds designed for heavier hybrid IndyCars. However, due to the decision to postpone the introduction of energy recovery systems until July, there was a discrepancy in vehicle weight. The cars were over 100 pounds lighter than what the tires were designed to handle. This will not be an issue in the 2025 race as the Firestone tires are now tailored to the cars, which have increased by 105 pounds from last year.
Krstolic anticipates a different approach to the tires in this year’s Thermal race due to the weight and performance of the hybrid. The alternate tire is not far off from what was used last year, but the additional weight and hybrid performance will result in interesting performance from the alternates. A significant drop-off and degradation are expected, but Krstolic assures that a good racing product will be delivered.
Following the Thermal race, IndyCar will return to California in April for the 50th running of the Long Beach Grand Prix. There, the split between primaries and alternates will be five sets each, and the rapid wear of alternates is predicted to continue. Feedback from drivers on this high-consumption of alternates will be a recurring theme this season.
Krstolic mentioned mixed feelings among drivers on the alternates in St. Petersburg; some thought the degradation was too high, making managing them during the race challenging. However, IndyCar’s goal was to have a tire that would drop off early to create a difference in racing strategies. Krstolic emphasized that while driver feedback is crucial in their design cycle, they also consider the feedback from IndyCar, who prioritize the overall quality of the race. Despite mixed reactions, drivers understand the direction IndyCar is heading towards. The same tires will be used for Long Beach, and the season is set to be an exciting one.
