Rider control in bicycling is modeled by first adding the rider as a passive mechanism to the Whipple bicycle model. Next, for the rider control model a linear PID controller with and without delay is assumed, where the control inputs are the bicycle roll and steer angle with their higher derivatives, and the control output is the action-reaction steer torque applied by the rider at the handle bars. The experimental data is obtained from riding a bicycle on a narrow treadmill while applying an intermitted lateral perturbation by means of an impulse force applied at the seat post. The experiments are conducted in both the stable and the unstable forward speed range. After some filtering, a parametric control model is fitted to the data. Finally, the gains of this control model are used to identify the specific optimal control LQR cost function which the rider is using to control the bicycle on the treadmill at the various forward speeds.@en