Torsion vs Extension Garage Door Springs, Explained

Every overhead garage door has springs, and they do most of the lifting. The opener just guides the door up and down. When a heavy door feels light in your hands, that is the springs doing their job.

There are two main types, and you can usually tell which one you have without touching anything.

Torsion springs: the bar above the door

Torsion springs are mounted on a steel shaft that runs across the wall just above the closed door. You may see one spring or two, usually near the middle of the shaft. At each end of the shaft sits a drum, a small grooved wheel that the lift cable wraps around.

When the door is closed, the spring is wound tight. As the door opens, the spring unwinds and turns the shaft, the drums turn, and the cables help lift the door. The tension is set by winding the spring with special bars, which is exactly why this is dangerous work.

• Smoother movement. The lifting force is spread across the shaft, so the door tends to travel evenly.
• Contained when it breaks. A broken torsion spring usually stays on the shaft. You often hear a loud bang and then see a gap in the coil.
• Common on heavier doors. Larger, insulated and wood doors often use torsion springs.

Extension springs: along the tracks

Extension springs run alongside the horizontal tracks on each side of the door, up near the ceiling. They are long springs connected to pulleys and cables. When the door closes, the springs stretch. When it opens, they pull back in and help lift the door.

• One on each side. They work as a pair, so both need to be in good shape for the door to stay level.
• Most tension when the door is closed. That is when they are stretched the furthest.
• They need safety cables. A properly installed extension spring has a safety cable running through the middle of it. If the spring breaks, that cable keeps the pieces from flying across the garage.

If you don't see a thin cable running through the center of each extension spring, mention it to a professional. It's a simple safety step that is sometimes missing on older setups.

How to tell which one you have

Close the door and stand inside the garage, clear of the door's path. Look at the wall above the door. A bar across the top with one or two thick coils on it means torsion springs. If that area is empty and you see long springs running along the ceiling tracks on each side, you have extension springs.

If you're not sure what you're looking at, a photo and a quick question to a professional will settle it.

What wear looks like on each type

Look, don't touch.

• A gap in the coil. On a torsion spring, a visible break in the coil means it has snapped.
• Stretched or uneven coils. On extension springs, coils that look spread apart, or one spring that looks longer than the other.
• Rust. Rust adds friction and can weaken the coils over time.
• A door that feels heavy or lifts unevenly. That usually points to a spring that has lost tension, or a pair that no longer matches.

Our guide to spring warning signs goes into more detail, and signs your door is out of balance explains how worn springs change the way the door moves.

Why spring work is never a DIY job

A garage door spring holds enough stored energy to help lift the full weight of the door. Releasing or adding that energy safely takes the right tools, training and a set routine. A slipped winding bar or a spring that lets go unexpectedly can cause serious injury.

That goes for both types. Don't adjust, unhook, wind, unwind or replace springs yourself. Don't loosen the set screws on a torsion spring, and don't remove the pulleys or cables on an extension spring system. Leave the cables and the bottom brackets at the lower corners of the door alone too, since they are tied into the springs. The same goes for garage door cables that look frayed or loose.

If you think a spring has broken, stop using the door. Don't run the opener, since it isn't built to lift the full weight on its own. Keep people and pets clear and call a professional.

Can you switch from one type to the other?

Sometimes. Some homeowners move from extension to torsion springs for smoother movement. Whether it makes sense depends on the door, its weight, the headroom above it and the hardware in place, so it's a decision to make with a professional who can see your setup. Either way, the springs have to match the door's weight.

A yearly tune-up includes an inspection of the springs and cables and a door balance test, which is the easiest way to keep an eye on either type. Here is what a tune-up actually checks.