Under certain conditions a Jeffcot rotor supported on fluid film bearings can experience undesirable stress reversals at double the operating speed in synchronous whirl. When the damping in the hearings is not considered, the condition for complete stress reversal coincides with that for backward whirling of the disk. However, when the damping also is considered, the absolute whirl directions of the journal and the disk can be different under certain conditions. Hence, the rotor shaft may not experience backward whirl throughout its length. Under these circumstances, the relationship between complete stress reversal and backward whirling motion is ambiguous. The present investigation specifies the precise condition for complete stress reversal and identifies it with the relative backward whirling of the disk with respect to the journal.Presented at the 45th Annual Meeting In Denver, Colorado