ASTM International

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
 N F2779

Annotation

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.

Tire operational severity, as defined as the running or operational temperature for certain specified internal tire locations, is not the same for these two test conditions. It is typically higher for the laboratory roadwheel at equal load, speed and inflation pressure conditions due to the curvature effect.

The practice applies to specific operating conditions of load range F through L for such commercial radial truck-bus tires.

The specific operating conditions under which the procedures of the practice are valid and useful are completely outlined in Section 6 (Limitations) of this standard.

It is important to note that this standard is composed of two distinct formats:

The usual text format as published in this volume of the Book of Standards (Vol 09.02).

A special interactive electronic format that uses a special software tool, designated as prediction profilers or profilers. This special profiler may be used to determine laboratory test conditions that provide equivalent tire internal temperatures for the tread centerline, belt edge, or ply ending region for the two operational conditions, that is, the curved laboratory roadwheel and flat highway test surfaces.

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.