The Tune-Up Tower is a 3 level structure with parking on the first 2 levels and a Dyno-Meter on the top floor.  This rolling treadmill is activated by a white switch on the tower roof.  The Dyno-Meter measures spinning wheel resistence and wheel alignment.  If a wheel is bent to the left then the car drifts to the left.  It makes sense that a car pushing into the sidewall of the track will encounter greater friction and run slower.