Definition
Garage door lift cables are aircraft-grade braided steel, typically 1/8" to 3/16" in diameter for residential doors. One end attaches to a fitting on the bottom bracket of each side of the door; the other end wraps around a cable drum mounted on the same shaft as the torsion springs.
As the springs unwind, the drums rotate and wind the cables, lifting the door. As the door closes, the cables unwind from the drums and the springs re-tension. Cable diameter is matched to door weight, over-spec is fine, under-spec is dangerous.
Cables fray and rust from the bottom up, where moisture pools at the bottom bracket. A frayed or slipped cable causes one side of the door to drop, slamming the door into the track and risking an off-track situation.
Why it matters to Nashville-area homeowners
Tennessee humidity is hard on garage door cables, we see corrosion at the bottom fittings on doors as young as 5–7 years in homes that don't pull the car out daily and don't get airflow through the garage. A frayed cable doesn't fix itself; it fails progressively until one snaps under load, and that's when the door comes off the track. If you see rust, kinks, or visible broken strands on a cable, stop using the door and call for service.
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How this definition is reviewed
Definitions reviewed against UL 325 (Underwriters Laboratories Standard for Door, Drapery, Gate, Louver, and Window Operators), CPSC 16 CFR Part 1211 (federal residential garage-door-operator safety rule), DASMA technical data sheets, and current manufacturer specs from LiftMaster, Chamberlain, Genie, Clopay, and Amarr. Locality notes draw on in-the-field experience in Middle and East Tennessee homes built between the 1960s and the present.
