<p>Flagellar motors enable bacteria to navigate their environments by switching rotation direction in response to external cues with high sensitivity. Previous work indicated that the ultrasensitivity of the flagellar motor originates from conformational spread, in which subunits of the switching complex are strongly coupled to their neighbours as in an equilibrium Ising model. However, dynamic single-motor measurements indicated that rotation switching is driven out of equilibrium, and the mechanism for this dissipative driving remains unknown. Here we propose that local mechanical torques on motor subunits can affect their conformation dynamics, based on recent structures observed with cryo-electron microscopy. This gives rise to a tug of war between stator-associated subunits that produces cooperative, non-equilibrium switching responses without requiring nearest-neighbour interactions. Our model predicts that the motor response cooperativity grows with the number of stators driving rotation, which is consistent with published experimental results. Finally, we show that operating out of equilibrium enables motors to achieve high cooperativity with faster responses compared with equilibrium motors. Our results indicate a general role for mechanics in sensitive chemical regulation.</p>