On sectional garage doors you will have one of the following spring systems, either extension or torsion. Both spring systems have their pros and cons and certain applications where they are best. In this article we will talk about extension spring VS torsion spring so you have a better understanding of each and when they should be used.
Extension spring systems consist of 2 extension springs, 4 pulleys and 2 sets of cables, the extension cables and the safety cables. Each spring is hung from the back hang of the garage door ( the punched angle iron that holds the horizontal track to the ceiling) and stretches from back to front. Each spring has a clip with a pulley attached and is hung from an S clip or similar device. The other 2 pulleys are attached to the horizontal track at the front of the door. These pulleys should be installed with washers to separate them from the track so they can spin freely. The extension cables attach to the bottom bracket of the door and loop around the front pulley and then the pulley that is attached to the spring, the cable is then attached to the horizontal track via a cable clip.
Due to each spring being set up individually, they are both pulling independently of each other which is the biggest fall back of an extension spring system and also the biggest difference between it and a torsion spring system. The major advantage of an extension spring system is the fact that they stretch over the horizontal tracks meaning less headroom is required for the installation of a door with extension springs compared to a torsion spring system.
Torsion spring systems consist of 1 or 2 springs on a 1” metal tube that are bolted to a center bearing plate, which gets attached to a 2 x 6 board called a spring pad above the door. On each end of the tube is an aluminum drum and an end bearing and plate that the tube goes through. The cables in this system attach to the bottom brackets of the garage door and wrap around the drums.
The way a torsion system works is that the springs and the dums are all connected to the tube using set screws to hold them in place. Each spring is wound and put under tension. As the door raises the springs unwind and the cables wrap around the drums as the weight is transferred to the horizontal tracks. These spring systems lift the door smoothly and evenly and are the most preferred spring system by professionals. A torsion spring system can lift more weight as well because of the springs. The only drawback is that they require more head room to install.
Each spring system has their strengths and weaknesses and applications that they are made for. If your garage doesn’t have a lot of headroom you may want to consider an extension spring system, however if you have a heavier door and the room a torsion spring system is the way to go.