A Practical Approach to the Selection and Sizing of Brakes to Meet FMVSS-121

A rational, practical method has been developed to size and select brakes which will meet the requirements of FMVSS-121 for a wide variety of truck models and sizes, with a minimum number of brakes. This paper presents the technique of utilizing Newtonian mechanics to categorize vehicle sizes and allow selection of common brake packages for each category. Actual sizing and selection was based on dynamometer test data.