LOSAIL, Qatar (AP) — Formula One drivers will have to change tires at least every 18 laps in the Qatar Grand Prix, which should make a three-stop strategy inevitable in the 57-lap race Sunday.

The governing body, the FIA, is acting over concerns that the Pirelli tires are being damaged when cars run over the pointed “pyramid” kerbs used at the Losail circuit.

The ruling means cars will have to stop at least three times unless the race is cut short for any reason. Cars that use the same tires for more than 18 laps will be considered to be "in an unsafe condition” and reported to the stewards, the FIA said. Any laps done in earlier sessions on tires that are then re-used for the race will count toward the total.

Tires analyzed after Friday practice showed signs that their interior structure was breaking down and there were similar signs in tires used in the 19-lap sprint race Saturday, even though that race had several safety-car periods when drivers slowed down.

The FIA and Pirelli suspect the problem is caused by “high-frequency interference” when cars run over the kerbs. Drivers have regularly been taking wide lines on the exit of corners to carry more speed, sometimes sliding across the kerbs in the process.

The track was already narrowed in one section Saturday by painting a tighter track-limit line in an effort to keep the drivers off the kerbs.

Max Verstappen starts on pole position for Sunday's race after the Red Bull driver clinched his third consecutive F1 title Saturday in the sprint.

___

AP auto racing: https://apnews.com/hub/auto-racing