This SAE Recommended Practice describes a test method for determining properties of a non-rolling tire quasi-statically enveloping, loaded onto, either a set of triangular cleats or a single step cleat. In the case of the triangular cleats the normal force and vertical deflection of the non-rolling tire are determined. In the case of the step cleats the normal force, longitudinal force, and vertical deflection of the non-rolling tire are determined. The method applies to any tire so long as the equipment is properly sized to correctly conduct the measurements for the intended test tire.(Footnote 1) The data are intended for use in determining parameters for road load models and for comparative evaluations of the measured properties in research and development.

NOTE - Herein, road load models are models for predicting forces applied to the vehicle spindles during operation over irregular pavements. Within the context of this document, forces applied to the pavement are not considered.

Procedures

A single procedure is specified. The difference in the test from the standpoint of the two cleat designs is in whether or not the wheel is free to rotate around the spindle and in what data must be measured and reported. This is spelled out in the body of 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. The test machine must be capable of accommodating the tire sizes to be tested, along with the required cleats.

NOTE - Test results are a function of the Tire/Wheel assembly, not just a function of the Tire alone.

Rationale

This document was developed as part of a set of Recommended Practices intended to allow modelers to determine the parameters required by any of the common tire models for calculating spindle loads given the road surface profile from a single set of experimental results, thus, eliminating duplicate testing.

Footnote 1 - Proper cleat height sizing requires that the test tire only contact the test cleat, and not the surface to which the cleat is fastened.