Eviction characteristics of two typical friction materials (non-asbestos organic and low-steel friction materials) for an automotive brake system were investigated using an inertial brake dynamometer. In particular, the effect of sliding speed on friction coefficient was carefully investigated employing various test modes. The two friction materials were developed for commercial applications and were different mainly in the type and the amount of metallic ingredients in the friction material. The dynamometer test showed that the low-steel friction material was sensitive to the sliding speed exhibiting a negative $mu$-v relation. On the other hand, the non-asbestos organic friction material was less sensitive to the sliding speed. The low steel friction materials with a negative $mu$-v relation also induced larger vibration amplitude during brake applications.