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This information report presents background and rationale for sAE recommended Practice J1106, Laboratory Testing Machine and procedures for measuring the Steady State Force and Moment Properties of passenger Car tires. Research experience is discussed in this information report, however, to the extent deemed necessary to provide background and rationale for the Recommended Practice. Material is therefore included on speed effects, contaminants, dynamic testing, traction, surface geometry, and other subjects not considered in the Recommended practice. the report begins with a general discussion of the factors affecting tire forces and moments, and a brief historical review of associated research and testing activities. A discussion is presented of the principal requirements for tire force and moment data as they derive from considerations of vehicle dynamics and tire design. Factors affecting test machine selection and design are reviewed in a broad context ranging from overall system structure to specific subsystem requirements. Methods for testing, data processing, and presentation and interpretation of test results are discussed in detail. The report concludes with a discussion of equipment and procedures for "special tests", not currently performed on a routine basis, but which provide data of significant and growing interest to the vehicle designer.