Torsion vs. Extension Springs: What's the Difference?
If you've ever looked up at your garage door and wondered what those big metal coils actually do, you're looking at one of two spring systems: torsion or extension. Both do the same basic job — counterbalancing the weight of the door so it can be lifted safely — but they work differently, and knowing which type you have matters when something goes wrong.
Torsion springs
Torsion springs are mounted horizontally on a metal shaft directly above the garage door opening. As the door closes, the springs wind up and store energy. As the door opens, that stored energy unwinds and does most of the work of lifting the door. Most homes built in the last few decades use torsion springs, usually one or two mounted side by side above the door.
Torsion springs tend to last longer and offer smoother, more controlled operation. Because the spring is contained on a shaft rather than stretching, they're also generally considered safer if something goes wrong — there's less risk of the spring flying across the garage the way an extension spring can.
Extension springs
Extension springs run horizontally along the upper tracks on both sides of the door, above the horizontal track section. Instead of winding and unwinding, they stretch and contract as the door moves. When the door closes, the springs extend; when it opens, they contract and pull the door up through a pulley system.
Extension springs are common in older homes and garages with lower ceiling clearance, where there isn't enough room to mount a torsion spring above the door. They're generally less expensive to replace, but because they store energy by stretching, a broken extension spring can release that energy suddenly. For this reason, extension springs should always be installed with safety cables that run through the spring and anchor it in place if it breaks.
How to tell which type you have
Look above your garage door. If you see a single metal bar with one or two tightly wound coils mounted horizontally right above the door opening, that's a torsion spring system. If instead you see long springs running along the upper horizontal tracks on either side of the garage, stretching and contracting as the door moves, that's an extension spring system.
Does it matter which one you have?
For day-to-day use, no — both systems work well when properly installed and maintained. It matters most when a spring needs to be repaired or replaced, since the two systems require different parts, tools, and techniques. If you're describing a problem to a technician over the phone, knowing which type you have can help them bring the right parts on the first visit. Learn more about spring repair