ASTM F2779-10(2016)

5.1 Historically, tires have been tested for endurance by a variety of test methods. Some typical testing protocols have been: (1) proving grounds or highway testing over a range of speeds, loads, and inflations, (2) testing on fleets of vehicles for extended periods of time, and (3) indoor (laboratory) testing of tires loaded on a rotating 1.707-m diameter roadwheel; however, the curved surface of a 1.707-m diameter roadwheel results in a significantly different tire behavior from that observed on a flat or highway surface.

5.2 Data from lab and road tire temperature measurement trials were combined, statistically analyzed, and tire temperature prediction models derived.5.2.1 The fit of the models to the data is shown as the coefficient of determination, R², for the two critical crown area temperatures, i.e. tread centerline and belt edge, as well as the ply ending area:

R² = 0.89, 0.90, and 0.89 respectively

5.2.2 These prediction models were used to develop the prediction profilers described in Section 7 and Annex A1.

1.1 This practice describes the procedure to identify equivalent test severity conditions between a 1.707-m diameter laboratory roadwheel surface and a flat or highway surface for commercial radial truck-bus tires.

1.2 The prediction profilers are based on empirically developed linear regression models obtained from the analysis of a large database that was obtained from a comprehensive experimental test program for roadwheel and flat surface testing of typical commercial truck and bus tires. See Section 7 and References (1, 2)2^,3 for more details.

1.3 For this standard, SI units shall be used, except where indicated.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.