The distribution function for generalized polytropic models has been used to construct a series of numerical models of anisotropic disks. It has been shown with the help of simulation that such systems are unstable with respect to bar formation at any degree of radial elongation of star orbits. The result is completely at variance with the conclusions of earlier works, where similar models were studied. The pattern speeds and amplitudes of the forming bar were found, and the initial distributions of orbit precession rates were calculated. Such systems have been shown to fulfill all conditions for the onset of radial orbit instability, responsible for the formation of a slow bar.