Results of numerical experiments involving the determination of possible causes of disk rim failure of a rotor wheel with blades, having the root of a dovetail joint type, are presented. The theory of coupling vibration of mechanical systems is used to elucidate the cause of rather high vibration stresses in the disk rim. Numerical investigation into the influence of specific features of the natural vibration spectrum of the rotor wheel as a system with cyclic symmetry and of the blade frequencies mistuning upon resonant vibrations have been performed.