What is Pacejka's Magic Formula? Pacejka curves are a big part of the tire models (and tire modeling is about 50% of a car simulator). They represent the forces that are generated by the tire as a result of the tire not following the road precisely. Steer the tire a little, and you get a slip angle, and this is input into the Pacejka Fy formula, giving a sideways force. Press the throttle, and the