Development for an Aged Tire Durability Standard – Stepped-Up Load Roadwheel Evaluation 2008-01-0150
In response to the TREAD act, ASTM F09.30 Aged Tire Durability Task Group was formed in 2002 with the objective of developing a scientifically valid, short duration, laboratory aged tire durability test which correlates to field behavior. The target end-of-test condition was belt edge separation (or related damage). One strategy, driven by that objective, has been investigation of an aged, stepped-up load test, modeled after the FMVSS 139 endurance test, but examining different velocities and step durations, plus oven aging durations. Testing was performed on two tire types where relevant field aging data was available from earlier NHTSA studies. Resulting end-of-test conditions were predominately non-representative of those seen in consumer use. These results have been associated with high tire temperatures, which in turn are linked with the high cyclic deflections caused by the specified load and pressure conditions. Aged stepped-up load testing did not seem a favorable approach to meeting the desired target.