Torsion spring vs extension spring

Garage door springs counterbalance the door's weight, allowing the opener (or human muscle) to move it with relatively little force. Two designs dominate.

Torsion springs mount horizontally on a shaft above the door opening. They twist (torsion) as the door opens and closes, storing and releasing energy. Standard residential lifespan: 10,000-20,000 cycles (7-12 years for typical use). When they break, the broken spring stays contained on the shaft. Modern installations use torsion springs almost exclusively.

Extension springs mount on either side of the door, parallel to horizontal track. They stretch as the door closes, storing energy that lifts the door. Lifespan similar to torsion (7-12 years). When they break, the spring can fly across the garage with significant force — a known safety hazard. Safety cables threaded through the spring prevent this; cables not present in older installations.

For garage door service operators, spring replacement is one of the most common service calls. Torsion spring replacement on residential doors typically takes 30-60 minutes and is appropriately priced at $300-$600. The work requires specialized tools (winding bars) and carries real injury risk if done incorrectly. Many operators upgrade extension-spring installations to torsion-spring during replacement when the door's age justifies it.