Various mechanical properties Including tensile strength of natural rubber (NR) and polybutadiene (PB) containing 10 phr of polynorbonene (PN)-vulcanizate- powder with the particle size ranging from 50 to 600 μm (average : 300 μm) were investigated. The amount of PN powder was varied up to 40 phr in order to investigate the effect of PN level on the properties of the carbon black-filled-natural rubber (FNR). Tensile fracture surface was observed using a scanning electron microscopy (SEM) in order to interprete the findings in the tensile test. The rate of cure of the rubber compounds increased but maximum torque decreased with adding PN powder. Addition of PN powder into PB rubber compound having lower tensile strength did not give any big changes in the tensile strength. However, in the case of NR compound which is stronger In tensile strength than the PN powder, the tensile strength decreased significantly with adding PN powder. The observed result was explained by two different fracture mechanisms found through the investigation of fracture surfaces. Typical 'Schallamach pattern' was observed and the surfaces among the ridges were found to be rougher as the PN powder was added. In the case of FNR compound, glass transition temperature, T_g stayed constant, tan δbetween 0∼70℃ and heat build-up increased and rebound decreased as the PN powder loading was increased. Skid resistance of FNR compound on a wet concrete at room temperature was found to be unaffected by the PN powder level of up to 40 phr.