Abstract: The flexible wheel is one of the key components in the harmonic gear wheel ransmission train. It determines the service life of the system. As the construction as well as the load are rather complicated, theoretical analysis of the dynamic stress of a flexible wheel pair is extremely difficult. An experimental study has therefore been accomplished with the telemetric measurements. A family of curves concerning the variation of stresses in characterest.ic sections of the flexible wheel is then obtained.The location of the critical section and factors influencing the critical stresses can be determined on the basir of the curves. These can be used to improve theoretical study and desigi techniques.