Extension spring systems use springs that stretch and retract to close and open your garage door. As the garage door closes, the extension springs which run along the horizontal track on each side of the door expand and are under great tension. Operating cables attached to the bottom of the door on either said offer counter balance strength. Safety cables help contain the springs in the event they break. As the door goes back up, the springs retract using that strength to pull the door to the open position.

Extension spring systems come with their own pros and cons. One advantage of this system is that each side of a spring system works independently to compensate for uneven ground. On the other hand, they require more parts, such as the pulleys and operating cables, and usually need more maintenance.