This study reports cryoEM structures of the bacterial flagellar motor's key component, the C-ring, in three states: counterclockwise (CCW) rotation, clockwise (CW) rotation, and CW rotation bound to a regulator. The C-ring, which contains multiple copies of protein subunits called FlhG, FlhF, and FlhN, is responsible for switching the flagellar rotation between CCW and CW. The structures reveal conformational differences between the CCW and CW poses, including a 180° shift in FlhF/FlhG domains that rotates the outward-facing MotA/B binding site to an inward-facing position. The regulator specifically binds to the CW pose, bridging elements unique to this conformation. These structures provide insights into how the switch reverses rotation and transmits torque to the flagellum, advancing our understanding of bacterial chemotaxis and bidirectional motor rotation. The study also discusses the torque transmission pathway and the role of response regulators in modulating rotation direction and speed.This study reports cryoEM structures of the bacterial flagellar motor's key component, the C-ring, in three states: counterclockwise (CCW) rotation, clockwise (CW) rotation, and CW rotation bound to a regulator. The C-ring, which contains multiple copies of protein subunits called FlhG, FlhF, and FlhN, is responsible for switching the flagellar rotation between CCW and CW. The structures reveal conformational differences between the CCW and CW poses, including a 180° shift in FlhF/FlhG domains that rotates the outward-facing MotA/B binding site to an inward-facing position. The regulator specifically binds to the CW pose, bridging elements unique to this conformation. These structures provide insights into how the switch reverses rotation and transmits torque to the flagellum, advancing our understanding of bacterial chemotaxis and bidirectional motor rotation. The study also discusses the torque transmission pathway and the role of response regulators in modulating rotation direction and speed.