  We show that for realistic equations of state of dense matter, the universal
proportionality factor relating the maximum rotation rate of neutron stars due
to mass-shedding limit to the mass and radius of maximum allowable mass
configuration of non-rotating models results from a universal proportionality
between masses and radii of static maximum-mass neutron stars and those of
maximally rotating configurations. These empirical relations cannot be obtained
in the slow rotation approximation.
