Torsion Spring vs. Extension Spring
The torsion spring is located about the garage door on a shaft. The torsion spring uses torque to raise the garage door, either by hand or by the garage door opener. The torsion spring slowly coils around the shaft when torque is applied. The torsion spring bears the weight of the garage door to move the door up and down the garage door track with the assistance of the garage door opener. It takes special tools to install a torsion spring above the garage door and should only be done be a professional. The torsion spring comes in many different sizes, make of steel, and lengths. Torsion springs can be used on residential garage doors as well as commercial garage doors. The best torsion spring to use is an oil rubbed spring, the oil keeps the spring lubricated for longer use.
One or two torsion springs?
On a two car garage you should have two torsion springs. Most residential one car garages have one torsion spring. We recommend having two installed on all garage doors, the reason for installing two torsion springs is that if one spring breaks then you have a second spring that can still pull up the garage door. Even on a larger garage door if one spring is broken, the other spring can still assist in lifting that garage door.
The extension spring is mainly used on a residential garage door. The extension spring is located along the outside of the garage door track running along the upper part of the track. The extension spring extends when the garage door is lowered and contracts when the garage door is pushed up. The extension springs are used mainly on a non-insluated garage doors that do now weigh much. Extension springs are not load bearing and should not be used on heavier garage doors. The extension springs also fail rapidly from the extending and contracting.
Two extension springs?
There are always two extension springs on garage doors, one for each side.
Which is better?
The torsion spring is a far superior to the extension spring because the torsion spring can handle a larger amount of weight, lasts twice as long, and the torsion spring offers a better overall balance on the garage door. Extension springs are exposed on the side of the track and have more pinch points, which can cause more harm. Torsion springs offer a much safer use since they are located above the garage door out of arm's reach.
Just remember that whichever spring is on your garage door, the torsion spring and the extension spring are both under a lot of tension. The tension of the spring can let loose at any time and cause you harm if you are doing anything to take off the tension on your own. You should always consult a garage door professional!