The P115 first appeared at the Dutch Grand Prix (along with the new Brabham BT24 and Lotus 49) but was not raced until the German Grand Prix at the Nürburgring. Stewart tended to go well at the Nürburgring and managed to qualify the car on the front row with the third fastest time of 8:15.2. Having dropped to seventh after the start Stewart managed to work his way back to third by lap 5 when his race was terminated by the same differential failure that had affected Spence's P83 earlier in the race.