What is the difference between a torsion spring and an extension spring?

Torsion springs mount horizontally above the door on a metal shaft and work by twisting (torquing) as the door moves. They're stronger, last 10,000–15,000 cycles, and are safer when they break because the shaft constrains them. Extension springs mount on the sides and stretch. They last 5,000–10,000 cycles and are more dangerous when they fail without safety cables.

Can I convert extension springs to torsion springs?

Yes. Converting from extension springs to a torsion spring system costs $350–$600 in NYC and is worth it for safety and longevity. The conversion requires a new header bracket, torsion shaft, spring, cables, and drums. Most extension-spring doors have enough headroom above the door for the torsion hardware.

How do I know if I have torsion or extension springs?

Look above the closed door. A single horizontal metal coil/bar across the top = torsion spring. Two coil springs running horizontally along the side tracks on either side of the door = extension springs. Extension springs are typically visible along the horizontal track sections.

Are extension springs dangerous?

Extension springs can be dangerous when they break if they're not equipped with safety cables (a cable running through the inside of the coil). Without a safety cable, a broken extension spring can thrash violently and fly into the garage. If your extension springs lack safety cables, have them added immediately — it's a $40–$80 addition that dramatically reduces the hazard.

← Back to Blog · 2026-05-04

Torsion Spring vs Extension Spring — What's the Difference and Which Is Better?

Quick Answer

Torsion springs (above the door, on a shaft) = stronger, 10,000–15,000 cycles, safer when they break. Extension springs (on the side tracks) = older design, 5,000–10,000 cycles, more hazardous when they fail. Torsion is the modern standard; conversion from extension to torsion costs $350–$600 and is worth it.

How to Tell Which Type You Have

Stand in your garage and look at the top of the door:

One or two horizontal coil spring(s) centered above the door on a metal shaft: You have torsion springs. This is the modern standard found on most doors installed after 2000.
Two coil springs running along the horizontal (ceiling-level) portion of the tracks on each side of the door: You have extension springs. Common in older homes, especially those with 7-foot ceiling clearance or lower.

Torsion Springs — How They Work

Torsion springs are mounted on a steel shaft that runs horizontally across the full width of the door, above the door header. When the door closes, cables pull on drums at each end of the shaft, which twists (torques) the spring coil and stores energy. When you open the door, the stored torque unwinds and helps lift the door weight.

The spring coil is captured on the shaft between two bearing plates and two winding cones. When a torsion spring breaks, the broken halves stay on the shaft — they can't fly outward because the shaft constrains them. The break is violent (loud bang) but the spring stays in place.

Lifespan: 10,000–15,000 cycles. High-cycle versions rated at 25,000 cycles available.

Extension Springs — How They Work

Extension springs mount on the horizontal track sections on each side of the door (the ceiling-level portions that run toward the back of the garage). As the door closes, the springs stretch and store energy. When the door opens, the springs contract and help lift the door via pulleys and cables.

When an extension spring breaks, it's under full stretch tension at the moment of failure. Without a safety cable running through the inside of the coil, the broken spring can fly outward with significant force — enough to damage property or cause injury. If your extension springs don't have safety cables (a cable threaded through the coil), this is a safety priority to fix immediately.

Lifespan: 5,000–10,000 cycles, or roughly 3–7 years with regular use.

Side-by-Side Comparison

Feature	Torsion	Extension
Mount location	Above door on shaft	Side tracks
Standard lifespan	10,000–15,000 cycles	5,000–10,000 cycles
Safety when breaking	Stays on shaft	Can fly (needs safety cable)
NYC installation (repair)	$280–$520 (pair)	$180–$280 (pair)
Common on	Post-2000 doors	Pre-2000, low-ceiling

Should You Convert from Extension to Torsion?

If your home has extension springs and you're already paying for a repair, it's worth asking about conversion. A complete extension-to-torsion conversion costs $350–$600 in NYC and includes a new torsion shaft, spring(s), drums, cables, and bearing plates. The benefits: longer spring life, safer failure mode, and better door balance (torsion provides more even lift across the door width).

The conversion requires a minimum of 2 inches of headroom above the door — most NYC garages have this. If the ceiling is extremely low (under 7.5 feet), a low-headroom torsion kit may be needed at slightly higher cost. Call and describe your ceiling height and we'll confirm compatibility before scheduling.

Spring replacement or conversion — same-day NYC.

We carry all calibrations for torsion and extension springs on every truck. ★ 4.9 / 5 (287+ reviews).

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