Tests Documenting Vehicle Handling with a Temporary-Use Rear Tire and a Run-Flat Rear Tire 2006-01-0905

Temporary-use-only spare tires are common standard equipment on motor vehicles while run-flat tires are offered as standard equipment on some motor vehicles. This paper describes testing on a 1995 GMC Safari all-wheel-drive minivan with a rear Uniroyal Hideaway / Temporary-Use-Only tire and a 1997 Mercury Grand Marquis with a self-supporting run-flat tire manufactured by Bridgestone. The testing included circle turn tests and 180° step steer tests at target speeds of either 30 or 35 miles per hour (low speed J-turn test). Control tests were conducted with standard normally inflated tires. Both the standard tires and run-flat tires were also tested in a modified condition involving the removal of the tread and outer steel belt, simulating a tire which has experienced a complete tread-belt separation. The principal conclusions of this work are that temporary-use-only tires have characteristics that do not degrade handling and response of a minivan and that the run-flat tires have characteristics that favorably influence the handling and response of a passenger car that has sustained a loss-of-pressure tire disablement.