Torsion vs. extension springs — which one is on your door?

The two spring types do the same job differently: they counterbalance the weight of the door so the opener motor (or your back, if you're going manual) doesn't have to lift 200 pounds of steel by itself.

Torsion springs

Mounted horizontally on a steel shaft above the door. They store energy by twisting. When the door comes down, the cables pull the drums on either end of the shaft, which winds the spring up. When the door goes up, the spring unwinds and helps lift.

You'll see one or two springs on the shaft. Most modern residential doors have two. They're usually black (oil-tempered, the industry standard) or silver-grey (galvanized — in our experience it doesn't last as long in Lower Mainland damp).

Failure mode: a visible 1- to 2-inch gap in the coil where the spring snapped and unwound. The sound is a sharp bang, usually loud enough to wake the dog.

Torsion is the standard on nearly every modern residential and commercial sectional door, and on most replacement installs since the late 1980s.

Extension springs

Mounted on either side of the door, parallel to the horizontal tracks. They store energy by stretching. As the door comes down, the springs stretch out. As the door goes up, the springs contract and pull the door open via cables and pulleys.

You'll usually see one long spring per side (occasionally two), each roughly 24 to 36 inches long, running horizontally just above the tracks.

Failure mode: the spring snaps and the broken ends whip loose at high speed. That's why extension springs need a safety cable running through the centre of each spring. If yours don't have one, you have a serious problem — not the spring, the missing cable. We won't service an extension setup without safety cables in place, because a spring that lets go without one can seriously injure someone.

Quick comparison

	Torsion	Extension
Position	Horizontal, above door	Horizontal, along tracks
Mechanism	Twists	Stretches
Lifespan (standard)	10,000 cycles, 5–10 yrs	10,000 cycles, 5–8 yrs
Safety	Self-contained on shaft	Requires safety cable
Modern installs	Yes	Being phased out
Cost to replace	Flat-rate, all-in	Usually convert to torsion

If you have extension, should you convert to torsion?

Often, yes. Torsion is safer, lasts about as long, and runs smoother. A conversion costs more up front than a straight extension-for-extension swap, because it adds a shaft, drums, and bearing plates — but you're paying for safety and a smoother door, not a cosmetic upgrade. The exception is a garage without enough headroom above the door for a torsion shaft, which is rare on residential builds — usually only an issue on very old or custom installs.

If your house is from the 1960s or earlier and still has original extension springs, you're long overdue. We'll quote both options and let you pick.

What about the cables?

Both systems use cables — different routes, same idea. The cables carry the spring's force to the bottom of the door, and they fray and corrode (humidity, salt) faster than springs do. If we're already replacing your springs, new cables are free with the two-spring tier. On a single-spring job they're a separate $120 line item — skip them and you're gambling on a $2,300 panel-and-tracks repair when one snaps later.

What about the gauge, length, and diameter numbers?

Torsion springs come in different inside diameters (1¾", 2", 2⅝"), wire gauges (.207 to .295), and lengths (20" to 40" for residential). The right spec depends on door weight and height. You don't need to memorize this — your tech does. We measure on site and pull the right spring off the truck.

The door doesn't lie. If it bangs and stops working, it's the spring. If it hangs crooked on one side, it's usually a cable. Either way, call.