This SAE Recommended Practice describes test methods for measuring and identifying the natural frequencies for the

lower order modes

of an inflated radial tire with a fixed spindle while expending modest effort and employing a minimum of test equipment. The methods apply to any size of radial tire so long as the test equipment is properly scaled to conduct the measurements for the intended test tire. Two types of boundary conditions are considered for the tire:

unloaded and loaded against a flat surface. The test involves the performance and measurement of an input vibratory force (excitation) to the tire and the corresponding vibratory output (response). The data are suitable for use in determining parameters for road load models and for comparative evaluations of the measured properties in research and development.