Torsion vs. extension springs, explained

Springs counterbalance the door so a 150-plus-pound object moves like it weighs ten. Torsion springs (a coil on a shaft above the door that lifts by twisting) equip most doors installed in the last 20 years. Extension springs (stretched along the horizontal tracks) are the older, lighter-duty system. Both are rated in cycles, not years, and both are replaced rather than repaired.

How the counterbalance works

A door's weight is carried by cables wound on drums at each end of a shaft; the spring twists (torsion) or stretches (extension) to pay that weight out and take it back. The opener only supplies the nudge. This is why a door with a broken spring defeats its opener: the motor is suddenly asked to deadlift the whole door, and it's not built for that.

Torsion: the modern standard

One or two springs on a shaft above the header. Smoother, safer in failure (the spring stays on the shaft when it breaks), easier to balance precisely, and available in a wide range of cycle ratings. Nearly everything installed in the Triangle since the early 2000s is torsion.

Extension: older and lighter

A spring stretched along each horizontal track, doing its work like a screen-door spring. Cheaper, but harder to balance evenly (each side works alone) and messier in failure, which is why every extension spring should have a safety cable running through it to catch the pieces. If yours doesn't, that's worth a service visit on its own. Many extension doors get converted to torsion at replacement time.

Cycles, not years

Standard springs are rated around 10,000 cycles: one cycle is one open and close. At four cycles a day that's roughly seven years; a busy household using the garage as the front door burns through it faster. That math is where the 7-to-12-year lifespan comes from. High-cycle springs (25,000 and up) cost moderately more and are the right call for heavy-use garages; ask on any spring visit.

What breaking looks like

A loud bang from the garage, then a door the opener strains to lift a few inches. On a two-spring door the survivor has the same mileage as the one that broke, which is why replacing both at once usually beats two service calls a few months apart. Typical prices are in the spring cost guide.