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. 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.