There are two types of springs used for garage door installation. These springs are used in both, manual as well as electronically-operated doors. They also produce the same tension in the other attached components of the garage door. Even a small scratch or nick can damage these springs permanently. Therefore, the springs and other hardware attached to the springs, need to be handled carefully for both, the safety of the person and the preservation of the spring.
Basically there are two types: torsion and extension springs. Usually the former ones are used for sectional roll-away doors, whereas, the latter ones are used for swing-up doors.
Torsion Springs: These work on the principle of 'twisting'. They are placed above the center of the door on a metal shaft, which is parallel to the edges of the door. There are strong cables attached to the bottom part of the door, with the help of which, the garage door opens and closes. When the torsion springs twist, these cables help lift the garage door. The door closes, when the springs extend. The torsion shaft which passes through these springs, prevents possible accidents due to spring failure.
Extension Springs: These work on the principle of stretching. They are located on the top rim of the garage door, on each side of the door track. They are also called side-mounted springs because of their position. They are long and heavy springs, attached to each side of the door. Efficiency of these springs reduces, because of the force exerted and excessive usage. These springs should be installed with a strong restraint cable through the center, which prevents possible accidents in case the spring fails.
The garage door and floor must be leveled properly. Without this leveling, garage doors do not close evenly. Time and usage reduce their efficiency. Both the springs used in the garage door function together. Therefore, even if one of them breaks, you need to replace both of them. If you replace any one of them with a new one, it will result in an imbalanced door opening mechanism.
Check your garage door springs and other parts of the garage door regularly. Make it a habit to check the whole system, once in a month. Always refer to the user manual first, before doing any repairing or replacement.