The retardation of an elastic rotating ring is considered. Bates has formulated a paradox indicating that as the ring slows down, unaccounted for elastic energy appears in the ring. I here show that, due to the relativity of simultaneity, the amounts of work performed at the two ends of a small element of the ring, are unequal, as measured in the instantaneous inertial rest frame of the element. So in addition to the work performed in order to stop the ring, some work is performed which compresses the ring. This work, which vanishes if Galilean kinematics with absolute simultaneity is used, fully accounts for the appearance of elastic energy in the ring.