Broken Springs on Heavy Highland Park Doors

One open and one close is a cycle. A standard set is built for something near ten thousand of them, which sounds generous until you count a household leaving for the train, coming back, and going out again. Homes that use the garage as the main way in get through a set years earlier than the arithmetic suggests.

Cold does not wear a spring out. It finishes one that was already done. Steel stiffens overnight, the first lift on a January morning asks for more than the metal has left, and the coil parts with a bang you can hear from the kitchen. Detached garages on the ravine lots are unheated, which is why those doors tend to go first in a hard freeze off the lake.

The technician measures wire diameter, inside diameter and wound length from the spring that failed, then checks that against what the door weighs. Two doors of identical width can want completely different springs, and a set that is close but not right runs rough and comes back early.

On a two-spring door both are replaced together. They were wound the same day and have carried the same load ever since, so hanging one new spring beside a tired one leaves the door out of balance. Before we leave, the opener comes off and the door is lifted by hand. A correctly balanced door stays where you leave it at chest height instead of dropping or climbing.