Look above your closed door: a steel shaft with one or two tight coils means torsion; long skinny springs stretched alongside the horizontal tracks mean extension, and the two systems fail, cost and behave differently enough that the difference is worth five minutes.
By Ryan Gold, lead technician, Reliable Garage Doors ยท Updated on July 19, 2026
A torsion system stores energy by twisting: cables on drums at each end of a shaft wind and unwind as the coil above the door center twists. The load path is symmetrical, which is why torsion doors travel straight and balance precisely. An extension system stores energy by stretching: one spring each side, anchored to the rear track hangers, pulling through pulleys. It works, but each side pulls independently, so wear shows up as crooked travel.
Torsion springs announce death with one loud bang and a visible two-inch gap in the coil; the door simply becomes too heavy. Extension springs fail two ways: a clean snap, or slow stretch-out where the door gets heavier and the opener strains for months. The dangerous difference: a torsion spring fails in place on its shaft, while a snapped extension spring whips through whatever is nearby unless a safety cable runs through its center. If your extension springs have no cable threading through them, that is a same-week fix costing very little.
On a new door or a rebuild, torsion wins on nearly every axis: cycle life, balance, safety behavior and adjustability. Conversions from extension to torsion are routine when there is roughly twelve inches of headroom above the door. Either way, spring sizing is arithmetic, not guesswork: door weight, track radius and cycle rating determine wire size, diameter and length. Undersized springs are the root cause behind half the burned-out openers we replace; the market cost of doing springs right is on our spring cost guide.
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Not reliably; the hardware lives inside above and beside the door. From inside, one glance up settles it: coil on a shaft above the door means torsion, stretched springs along the tracks mean extension.
The two sides age at different rates, so one spring pulls harder than the other. Matched replacement pairs restore even travel; replacing only one side rebuilds the imbalance.
Both store lethal energy; torsion requires winding bars and technique, extension requires safe de-tensioning. The DIY injury statistics do not distinguish; neither should you.
The same spring geometry built to 25,000 to 100,000 cycles instead of the standard 10,000, priced modestly higher. For busy family doors and commercial doors they are the cheapest longevity money can buy.
