INDIANAPOLIS (Saturday, May 3, 2025) – INDYCAR has announced an update to the race tire usage requirements for the Sonsio Grand Prix on the Indianapolis Motor Speedway road course on Saturday, May 10.
For the race, teams will be required to use:
- Two sets of alternate compound tires (one more than previously required)
- Two sets of primary compound tires (one more than previously required)
There are no requirements in terms of new (sticker) sets of tires used in the race. The two completed laps needed to satisfy the tire requirement rule, where one (1) lap must begin once the Green Flag has been displayed to the Race Leader (Rule 15.3.3.2.3.) for each of the four sets (Rule 15.3.3.2.) remains in effect.
The update strives to ensure an all-out, driving on the limit, thrilling and entertaining product for fans and generate even more strategic challenges for North America’s premier open-wheel racing series. Additionally – working with Firestone – the current, standard event weekend road and street circuit tire allocation that began this season (five sets of primaries and five sets of alternates) was contemplated with this tire requirement format option in mind. The tire allocation for the IMS road course, the only two-day road and street circuit event on the 2025 NTT INDYCAR SERIES schedule, remains unchanged at five sets of primaries and four sets of alternates.
“INDYCAR is continually looking into ways to improve an already extraordinary on-track product,” INDYCAR President J. Douglas Boles said. “Firestone is a terrific partner, and their higher degradation alternate tire has given strategists plenty to think about on road and street circuits this year. We expect this update will challenge teams and drivers even more.”
In an additional move to ensure more robust on-track activity during the Sonsio Grand Prix event, Practice 2 on the IMS road course will be adjusted from a limited green flag guarantee of 45 minutes to 35.
Following the event on the IMS road course, INDYCAR will review both updated procedures and evaluate its use for future races.
Coverage of the Sonsio Grand Prix, round five of the 2025 NTT INDYCAR SERIES championship, begins at 4:30 p.m. ET Saturday, May 10 on FOX, the FOX Sports app and the INDYCAR Radio Network. The first practice of the weekend is scheduled for 9:30 a.m. ET Friday, May 9 and can be seen on FS2.
The next NTT INDYCAR SERIES event is the Children’s of Alabama Indy Grand Prix powered by AmFirst on Sunday, May 4. Coverage begins at 1:30 p.m. ET on FOX, the FOX Sports app and the INDYCAR Radio Network.
