The effect of manufacturing parameters on friction characteristics of motorcycle break system was studied using a design of experiment. Such parameters conditions have an effect on the frictional factor such as applied load, sliding speed, and number of ventilated disk hole. However, it is difficult to know the mutual relation of these factors. In this study, the friction characteristics using design of experiment containing 3 elements were investigated for an optimal condition for the best motorcycle break system employing full factorial design. From this study, the result was shown that the applied load in frictional factors was the most important, next to sliding speed, number of ventilated disk hole.