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The development and validation of a brake pad insulator damping measurement procedure by the SAE Brake NVH Standards Committee is described in this paper. The details of the test procedure, test set-up and recommendations for proper test practices are described. The description provides an excellent foundation for evaluating the damping properties of a shim over a range of frequencies and temperatures. To document the repeatability of the measurement process, a Gage R&R study was conducted. The results show that a high level of repeatability is achieved over a range of temperatures and damping properties. An example application is described to illustrate the usage of the procedure. This example provides an excellent illustration of how this procedure can be used to select the best shim for a specific application. Conclusions as to the applicability of this procedure and its value to brake noise control are provided in the final section.

A summary of the committee engaged in the development of a revised SAE J57 Truck Tire Noise Measurement Standard is presented. This discussion reviews the evaluations of the current standard, current and proposed international standards, and the key changes in the proposed revision to SAE J57. A major expansion to the scope of the current standard tackled by the committee was the effect of environmental conditions. The effects of road surface temperature, ambient air temperature, and wind are discussed. The measurement limitations and corrections implemented to address these factors are also described. Another key issue discussed is the effect of pavement surface. Cited references indicate that the effects of road surface variation can be greater than tire design differences. The committee developed a specification for a standardized surface to address this concern. Another improvement of the current standard is in the specification of tire operating conditions.

A description of the confirmation tests conducted by the Tire Noise Standards Committee for the revised J57, Truck Tire Noise Measurement Standard is presented. The goal of these tests was to determine the repeatability and variability associated with the procedures and ranges of parameters specified in this revision. Two sets of tires were tested over a range of measurement parameters. The parameters examined included tire type, ambient temperature, pavement surface temperature, coast-by speed, and trailer drawbar length. Finally, the total coast-by noise measurement variability according to this new procedure is estimated.

It is difficult to quantify the portion of coasting vehicle noise that is due to tire-pavement interaction alone. There are often contributions from aerodynamic noise of the vehicle, transmission whine, noise from suspension components, and other miscellaneous sources. The towed-trailer method used in the revised SAE J57 standard has been shown to be an effective means of isolating tire-pavement noise for truck tires. This paper reports the results of a test program conducted by SAE Tire Noise Standards Committee to evaluate the feasibility of towed-trailer coast-by testing of passenger and light truck tires. The results of tests conducted in April 1996 at the Ohio Transportation Research Center are described and they indicate that accurate measurements are possible for towed-trailer testing of passenger tires. It is shown that a key aspect of performing such a test is reducing the noise of the tow vehicle and that sufficient reduction is possible even for extremely quiet test tires.

As other vehicle systems have become more refined, more attention must be placed on brake NVH issues because they can cause a negative customer experience. From the laboratory to the road, the use of technology as well as further study by engineers is helping to lessen noise, judder, and vibration in cars. This book provides readers with a fundamental understanding of current practices for measuring and testing brake NVH. From coverage of basic definitions and concepts to in-depth analysis of on-road testing procedures, it will serve as a comprehensive reference guide for brake test technicians, test engineers, lab managers, and others who work on making brakes quieter, smoother, more refined, and more reliable. Readers will learn how to test for brake noise, what tools to use, and which recent standards and practices have led to the successful measurement of brake noise and vibration.