IndyCar announces big change before inaugural Thermal Club GP

IndyCar has announced a major rule change ahead of the 2025 Thermal Club IndyCar Grand Prix. The event will be the first points-paying race at the venue.

For the first time in 2024, IndyCar tested the permanent road course at the Thermal Club in California. In March, the series organized a one-off 20-lap event, called the $1 Million Challenge, which Alex Palou won.

The NTT IndyCar Series is set to inaugurate its first-ever points race at the same venue. However, ahead of the event, the series confirmed a rule change concerning tire allocation. The decision comes after the series’ experience at St. Petersburg earlier in the season, where a new tire policy led to the rapid degradation of alternate tires.

At St. Petersburg, the teams received five sets of the softer, less durable alternate tires and five sets of the harder primary tires. However, the distribution will revert to six primary and four alternate sets for the Thermal Club GP.

The decision to modify the tire allocation stems from concerns regarding performance consistency and tire wear. After Thermal, the series will return to California in April for the 50th running of the Long Beach Grand Prix, where the original 5-5 tire split will return.

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IndyCar chief engineer elaborates the reasoning behind rule change ahead of Thermal GP

Firestone’s chief race tire engineer, Cara Krstolic, explained the rationale behind the rule change in a recent interview with RACER. She highlighted how IndyCar’s discussions with Firestone led to a renewed focus on tire strategy.

"When we talked to IndyCar over the off-season, they said we need more interest coming out of the tires. So, anything that we could do to widen the gap and make the alternate truly wear out, as opposed to having an alternate that’s pretty much there over a full stint, which was just not going to provide very good racing," she said.

Krstolic explained that instead of simply making the alternate compound softer, Firestone opted to reinforce the primary tire for added durability.

"So what we went through for Thermal is a little bit of a different approach. Instead of trying to make the alternate softer, as we did at our street courses, what we’re doing is putting more toughness into the primary tire," she added.

Alex Palou enters the Thermal Grand Prix as the points leader. The Chip Ganassi Racing driver emerged victorious in the season-opening race at St Petersburg.