Experimental Investigation on the Effect of Tire Pressure on Ride Dynamics of a Passenger Car 2019-01-0622

Ride is essentially the outcome of coupled dynamics of various involved sub-systems which make it too complex to deal analytically. Tires, amongst these, are known to be highly nonlinear compliant systems. Selection of tires specifications such as rated tire pressure, etc. are generally decided through subjective assessment. While experts agree that tire pressure affects the attributes such as ride to a noticeable degree, the quantification of the change often remains missing. In the current work, vibration levels of various sub-systems relevant to ride in an SUV are measured for three different tire pressures at different speeds over the three randomly generated roads. For the purpose, artificial road profiles of classes A, B and C are synthesized from the spectrum of road classes defined in ISO 8608:2016 and reproduced on a four-poster test rig. Various ride performance metrics such as weighted root mean square (RMS) acceleration, primary ride, secondary ride, frequency responses etc. are measured and compared across the tire pressures (29, 32 and 35 PSI) on an SUV vehicle. Key findings include a trend of increasing weighted RMS and higher amplitude responses near the dominant natural frequencies of human-vehicle system. Paper concludes with several useful insights into human-vehicle ride dynamics with respect to tire pressures.