The spin cut-off parameter of the nuclear level density and effective moment of inertia for a large numberof nuclei have been determined from analysis of the experimental data on S-wave neutron resonances and spins of low-lying levels. Contrary to claims made before, it is shown the spin cut-off parameter differs considerably from theircorresponding rigid body values, and the energy dependence of the effective moment of inertia confirms the interactingfermion model prediction. The spin cut-off parameter of the nuclear level density and effective moment of inertia for a large number of nuclei have been determined from analysis of the experimental data on S-wave neutron resonances and spins of low-lying levels. Contrary to claims made before, it is shown the spin cut-off parameter differs considerably from theircorresponding rigid body values, and the energy dependence of the effective moment of inertia confirms the interactingfermion model prediction.