Research Report RR:F09-1002
The U.S. TREAD Act of 2000 mandated the review and revision of the tire safety standards for radial passenger, light truck, and truck/bus tires.ASTM F09.30, through a specific commercial truck/bus tire test development task group, undertook the task of identifying, developing, and proposing appropriate roadwheel testing algorithms for DOT Federal Motor Vehicle Safety Standard (FMVSS) 119 compliance tests for load range F and above, radial commercial truck/bus tires.Most of the standardized endurance and high speed tire tests performed by the tire industry are on the standard 1.7 m (67”) diameter roadwheel. There are several adverse effects of this size roadwheel upon truck tires because of the relative diameter differences involved; e.g.•severe reverse curvature at the tire contact patch;•distortion of the tire’s intended contact patch shape;•altered/increased tire footprint pressures/distribution;•increased tire sidewall deflection.Based on its study of representative tires from long haul, bus, mixed service, regional, and urban commercial truck applications, the ASTM F09.30 task group on radial commercial truck/bus tire test development achieved the following results which are contained in this ASTM Research Report RRF09-1002: 1) “highway equivalent speed” algorithms for laboratory roadwheel testing to replicate road operating temperatures, and, conversely, road/flat surface testing to replicate roadwheel operating temperatures;2) “highway equivalent speed” algorithms” based upon steady state tire temperatures under a variety of operating conditions evaluated in the study’s design of experiments (DOE);3) algorithms that provided guidance on how to modify road operating conditions for use on a roadwheel to mitigate the roadwheel diameter effects primarily by establishing equivalent belt edge temperatures and secondarily upon tread centerline temperatures to avoid atypical test removal conditions;4) test removal conditions correlated to road removal conditions;5) a standardized laboratory endurance test;6) a standardized laboratory high speed test. The roadwheel tests were indexed to the recommended maximum speed of a specific tire and therefore compensated for roadwheel curvature effects via a reduction in roadwheel speed. Such tests were capable of discriminating between tire designs and providing a rank order with respect to ‘hours to removal’.It is intended that the results from the F09.30 task group’s work will prove valuable for both radial commercial truck/bus tire development and routine monitoring/auditing tests of radial commercial truck/bus tires.RR-F09-1002 provides the supporting data for ASTM F2779-10 “Standard Practice for Commercial Radial Truck-Bus Tires to Establish Equivalent Test Severity Between a 1.707-m (67.23-in.) Diameter Roadwheel and a Flat Surface” Discussions and conclusions contained herein apply only to the classes of tires included in this work. ASTM F09.30 reserves the right to modify the conclusions and/or recommendations within this report based upon any subsequent work and experience.
F2779-10 Standard Practice for Commercial Radial Truck-Bus Tires to Establish Equivalent Test Severity Between a 1.707-m (67.23-in.) Diameter Roadwheel and a Flat Surface
Committee F09 on Tires
Subcommittee F09.30 on Laboratory (Non-Vehicular) Testing