Objective Measurement of Vehicle Steering and Handling Performance When a Tire Loses Its Air

There have been several recent articles published concerning the effect of a tire tread separation on vehicle handling, but lately the literature has been silent on the situation where a tire airs out. This paper studies how various vehicles steer and handle during and after a tire deflates while the vehicle is traveling at speed. Utility vehicles, pickup trucks, and vans were tested by deflating front and rear tires. The air out condition was created by using a special test device that fired a twelve gauge shotgun shell at the sidewall of a tire while the vehicle was traveling at freeway speeds. The vehicles were instrumented with on board video equipment and a computer with transducers to measure both driver inputs and vehicle responses during the testing. The results show that a rapid tire air out creates a slight pull to the side of the deflated tire which then requires a small corrective steer to maintain a straight ahead course. A deflated tire also experiences a reduction in the cornering stiffness so that steering and handling is degraded. However, the air out did not force any of the test vehicles out of the driver's control. Vehicles still maintained maneuvering capacity which allowed the driver to control the vehicle and to easily bring it to a stop.