Effects of Anti-Sway Bar Separation on the Handling Characteristics of a SUV

A single-vehicle crash involving an SUV led to the study of the failure of the anti-sway bar linkage and tire pressure and their relative effects on the handling characteristics of the vehicle. The SUV, having been involved in a rollover, was found with the anti-sway bar drop link disconnected from the suspension lower A-arm assembly. Also, after the crash, the tire pressure in the front tires on the subject vehicle was measured to be above the value specified by the SUV manufacturer; however, the pressure for one of the rear tires was measured to be roughly half of the SUV manufacturer’s recommended pressure. The other rear tire was deflated. The testing described herein addresses the question of what effects the anti-sway bar drop link disconnection or reduced rear axle tire pressure would have on the SUV’s pre-accident handling and driveability. A procedure for evaluating vehicle understeer and oversteer characteristics as specified by SAE J266 was employed to evaluate the yaw and roll plane characteristics of an exemplar vehicle. Testing was designed to include an exemplar SUV in a constant radius, increasing speed maneuver, as well as, single and double lane changes. Additionally, the characteristics of the handling of the SUV was also evaluated relative to low tire pressure for the rear axle tires. Thus, the exemplar SUV was tested with the recommended pressure on both the front and rear axle tires with the anti-sway bar connected and then disconnected; moreover, these tests were repeated with the front tires at the recommended tire pressure and the rear tires at approximately half of the recommend tire pressure according to the SUV manufacturer. From the results of these studies, conclusions regarding the relative effects of a disconnected anti-sway bar and reduced rear axle tire pressure on the stability of the subject SUV could be determined.