Lock the bicycle into a stationary trainer, and mount the bicycle. Place each foot into its respective Look pedal. If you do not have stationary bicycle trainer, take your bicycle outside for a short ride.
Pedal the bicycle for upwards of a minute. Make note of how each pedal feels. If you feel any movement between the cleat and pedal, the pedal binding is too loose.
Unlock one foot at a time from the pedals and stop. Your feet should emerge from each pedal with little effort. If you struggle to remove either foot from its pedal, the pedal binding is too tight. While a tight pedal binding may be fine for riding, being able to unlock your feet in time as you come to a stop is essential to your safety.
Dismount the bike and locate the screw at the rear of the pedal. There is an arrow on either side of the screw, one marked (+) and the other (-).
Use a 3 mm Allen wrench-also a called a hex wrench-and turn the screw in the appropriate direction. Turning the screw toward the (+) sign will tighten the binding. Turning the screw toward the (-) sign will loosen it.