TYPES OF GARAGE DOOR SPRINGS
Most residential garage doors have one of two types of springs: torsion or extension. Torsion springs are heavy-duty springs mounted to a metal rod that runs parallel to the door, directly above the door opening. These springs are loaded, or tensioned, with a twisting action. When the door closes, cables attached to the bottom corners of the door pull on pulleys attached to the ends of the metal rod the springs are mounted on. The pulleys turn the rod, which twists the springs and creates tension. When the door is opened, the springs unwind and help lift the door.
Extension springs are long, lighter-weight springs that run perpendicular to the door and are mounted above the horizontal portions of the door tracks. These springs are tensioned by stretching out, using cables and pulleys, as with the torsion system. Because extension springs are merely suspended between two brackets (they are not mounted to a rod, like torsion springs), they must have a safety cable running through each spring. This helps contain the spring in the event of a breakage. Without the safety cable, a spring breaking under tension is a very serious safety hazard. If you have old springs that don’t have safety cables, you should install them even if you aren’t replacing the springs.
SYMPTOMS OF FAILING SPRINGS
Aging garage door springs cause the door to effectively “weigh” more as the steel loses its resiliency. With new springs, a heavy garage door should take no more than about 10 pounds of force to lift into an open position. With springs nearing the end of their lifespan, the force required to lift the door can be considerably more, since a garage door may weigh 200 pounds or more.A garage door with aging springs puts an enormous load on a garage door opener, so another sign of failing springs is when you hear the electric door opener begin to strain as it attempts to lift the door. At this point, it is time to consider replacing the springs. Aging door springs can also break suddenly, a situation that can cause the door to slam shut violently. If you happen to be present when a spring breaks, you will hear a very loud sound like a gunshot, because the break usually occurs when the spring is fully loaded—stretched or twisted to its full tension. When one spring breaks, the door will suddenly feel very heavy when you try to open it by hand, and an automatic garage door opener may no longer be able to lift the door at all.
Garage door springs cannot be repaired. Maintenance involves full replacement of both springs at the same time.