Garage Door Springs
Garage doors have two different types of springs. One is known as torsion springs, and the other is extension springs. Both of these springs are used to counterbalance the weight of the garage door, allowing you to easily lift something that should be too heavy for the average person to lift. How can you tell which type of spring you have?
Look directly above the garage door. If you've got a spring that stretches and contracts as the door opens and closes, and that is mounted above the horizontal tracts, you have an extension spring. If, however, you've got a spring that is mounted on the bar that is directly above the door and that winds and unwinds as the garage door opens and closes, you've got a torsion spring.