This SAE Recommended Practice describes a test method for determination of steady-state heavy truck (Class VI, VII, and VIII) tire force and moment properties under free-rolling conditions. The properties are acquired as functions of incrementally changed slip angle and normal force using a sequence specified in this document. The data are suitable for use in vehicle dynamics modeling, comparative evaluations for research and development purposes, and manufacturing quality control. Truck Tires-For the purposes of this document, truck tires are defined as being the tires mounted on all heavy commercial over-the-road trucks and buses. Examples of vehicles which use heavy truck tires include: tractor/semi-trailer combinations, dump trucks, school buses, etc. Tires mounted on other types of lighter GVWR vehicles are explicitly excluded from consideration in this document. Effects Not Considered-The effects of inclination angle and spindle torque or any combination of inclination and spindle torque with slip angle and normal force are not considered in this document. Test Machines-This document is test machine neutral. It may be applied using any type of test machine capable of fulfilling the requirements stated in this document. By way of example, specific data used in support of various parts of this document came from both an indoor flat-belt type machine and outdoor over-the-road dynamometer. This document does not require a machine to match the ideal machine, but does require that a test machine?s performance be fully defined over its range of application. In this document, an ideal is a goal not a requirement. Ideal Machine An ideal machine is a machine which is capable of fully matching every item in this document. Such a machine neither exits at the time this document was written nor is it certain that the technology to build such a machine exists at this time.