BIAS REGULATED ROLLING TRUCK BED COVER

A tonneau system that includes one or more tonneau sections and a retraction system. The retraction system has an adjuster shaft; a bias member; a drive roller in communication with the adjuster shaft; one or more lines connected to the one or more tonneau sections and/or to the drive roller; and an adjuster to adjust torque provided by the bias member. The bias member is connected to the adjuster shaft, the drive roller, or both.