The purpose of this study is to obtain a foundation data for chassis design and road noise reduction of automobiles. Using the combination of the automobile, radial tires and instrumentation equipment, experimental investigation were carried out to examine the characteristics of the structural vibration of tire as the key to obtaining the effective parameters for reducing road noise. From the results of experimental studies it has been confirmed that the existence of important frequency ranges, which were attributable to the suspension and chassis system. The tire, axle and chassis natural frequency of automobile govern the road noise. Results that material property of tire and experimental condition are parameter for shifting of tire natural frequency, which enables a designer of an automobile to foresee the influence of the various design factors on the road noise.