Reference · Spring sizing
Torsion spring sizing tool
The desk sizes a two-spring residential assembly from three measurements: the door weight in pounds, the door height in feet, and the number of spring turns the drum and cable lift allow. It then picks the smallest catalog wire that carries half of the required torque on each spring.
Worked examples
| Door | Required IPPT | Schedule |
|---|---|---|
| 150 lb · 7 ft · 7.5 turns | 703.7 | 2 × .281 in, 744 IPPT, 30,000 cycles |
| 120 lb · 8 ft · 8 turns | 603.2 | 2 × .273 in, 684 IPPT, 27,000 cycles |
| 90 lb · 6 ft · 7.5 turns | 361.9 | 2 × .234 in, 402 IPPT, 17,000 cycles |
| 220 lb · 8 ft · 7.5 turns | 1,179.6 | Over capacity for two residential springs |
The formula behind these figures is on the spring torque formula page, and the wire catalog is on the spring size chart.
Size your own door in the desk
Torsion springs store dangerous energy. These figures are planning guidance based on entered measurements. A trained garage-door professional must verify measurements, spring compatibility, winding direction, hardware limits, and safe winding procedures.
Garage Door Torsion Spring Desk Official Field Workpaper
Record Specification: Torsion spring sizing tool | Operations Compliance Record
Torsion spring quick sizing
Enter the door numbers and read the required torque and the recommended spring pair instantly. The live desk holds the full job spec.
Required 251.3 IPPT · recommended pair: .243 wire at 232 IPPT each.
Related Garage Door Tools & Checklists
Verified workflow modules running client-side with instant data hand-off.