The Art of Measuring Noise from Vehicle Tires 931275
During the latest decades tirelroad noise has been recognized as one of the most significant parts of road traffic noise. It has therefore become necessary to employ suitable noise reduction measures on tires as well as road surfaces which do not impose safety problems. Since many of these measures rely on appropriate measuring methods, several activities in order to standardize such methods for tirelroad noise have started.
The paper begins with a systematic analysis of the rather complicated tirelroad noise problem and suggests ways to solve it. Then a review is presented of the major measuring methods considered for standardization with regard to classification of tires:
The coast-by method
The trailer method
The laboratory drum method
The trailer coast-by method
The advantages and disadvantages as well as which applications are the most suitable for each one are discussed. Particular attention is paid to the extremely important question of test track surface selection. Especially, the surface recently standardized by ISO for vehicle noise tests is compared to a surface more representative of actual road conditions. Other parameters considered include temperature, speed and microphone positions.
Standardized measurement methods are necessary not only for classification of tires but also for classification of road surfaces. Therefore, the paper includes a status review of work going on in an ISO group which aims at standardizing a method for classification of the noise properties of road surfaces.
Finally, it is emphasized that due to the many parties involved and the risk of working out too many and separate methods, it is absolutely necessary to co-ordinate the efforts internationally.