A method for characterizing a stick-slip condition in a steering system includes transmitting a periodic steering control signal to a rotary actuator to cause rotation of a steering shaft, through a torsion bar and inertia wheel, over a range of steering angles, and applying an axial force to a rack to resist rack displacement from a centered position. A steering torque output value is measured via a torque transducer. A control action is executed when a measured difference between a maximum value of a steering torque required to initiate rack motion/torque breakaway and a minimum value of the steering torque after breakaway for start-up or subsequent steering reversal exceeds a calibrated threshold. A system includes the rotary actuator, steering system, torque transducer, torsion bar, inertia wheel, linear actuator(s) providing an axial force along the rack axis to resist rack displacement from a centered position, and controller programmed as noted above.