A condition which directly influences the dynamic performance of the roller clutch is roller float. Roller float is defined as a condition where the roller loses contact with the roller-way. Runout of the roller-way can create this condition. When the over-running speed of the inner race is high enough and the roller-way runout great enough, the roller inertia force will be of sufficient magnitude to overcome the spring force. To investigate this condition the method of kinematic equivalence is employed. The analytical results indicate the potential hazards of excessive raceway runout, and these results are supported with experimental evidence.