Kammala jumla mai zuwa: A cikin F1, bayan farawar da ya yi alkawari a shekarar da ta gabata, 1966 ba shekara ce mai kyau ba ga Stewart; H16 BRM mai lita 3 ba shi da aminci, kodayake Stewart ya lashe Grand Prix na Monaco a cikin motar mai injin lita 2. A mafi muhimmanci taron a wannan shekara shi ne ya hatsari a
Grand Prix na Belgium a Spa-Francorchamps, wanda ya haifar da kamfen dinsa don inganta aminci a F1 kuma ya sa ya rasa Grand Prix na Faransa a Reims.