Possibility of speed reducing with high intensity is one of the most significant dynamic parameters conditioning usage safety of vehicles in road traffic. Although cars' braking effectiveness was broadly recognized and described (Dudziak, 2002; Gaca, 2002; Gillespie, 1992; Ślaski et al., 2001), but there are considerable difficulties with finding information concerning motorcycle braking effectiveness. In this elaboration there are presented results of braking of sport motorcycles Honda CBR 900RR (sport motorcycle of high engine cubic capacity and high horsepower) and Junak Millenium (motorcycle rated to two-wheel vehicles class type cruiser). Results of carried out road tests were registered with measuring system of our own design based on acceleration sensors and piezogyroscope. During tests, motorcycles were accelerated and then broken with maximal possible to obtaining deceleration.