A study was conducted to determine if a safe upper service limit can be set for aircraft tires, based on an operation profile of the aircraft using the tires. The study consisted of three parts: development of a tire heating model, experimental confirmation, and determination of tire degradation as a function of time at temperature. Three operational profiles were identified: long, intermediate, and short haul; these stressed tires in different ways. The mathematical model, which calculated temperature as a function of time for various axial and lateral forces at different speeds, was developed and confirmed by experiment. It predicted the time at temperature of the hottest part of a tire that is exposed to the operating environment of the profiles. The impact of heating was found from a determination of ply adhesion as a function of time at temperature. The end of tire life was judged to occur when ply adhesion was degraded by 50%.