Before ordering a replacement spring, one question must be asked: is your door equipped with torsion springs or extension springs? The answer determines everything else, from compatible parts to necessary tools, and even safety instructions. Yet, many homeowners are unaware of this, as the system is largely hidden in the header or along the tracks.
This article explains how each technology works, compares their strengths, and gives you a simple method to identify yours in a few seconds. It is part of our series dedicated to springs, which starts with the complete guide to sectional garage door springs.
The torsion spring: a system installed above the door
The torsion spring is wound around a horizontal shaft fixed above the opening, just below the garage ceiling. At each end of the shaft is a drum onto which a cable connected to the bottom of the door panel is wound. When the door goes down, the cables unwind from the drums, the shaft rotates, and the springs twist, storing energy. When the door goes up, the springs unwind and release this energy, lightening the movement.
This system is appreciated for the consistency of its operation: the effort provided is progressive, and the door moves smoothly. Conversely, it requires a bit of available height in the header, and it involves significant tension. This is why adjustment and replacement must be performed with appropriate winding bars and in compliance with safety instructions. Associated parts include the shaft (hollow shaft or solid shaft), the drums, and the bearings.
The extension spring: two springs along the tracks
The extension spring, also known as a tension spring, works in the opposite way. It is placed on each side of the door, parallel to the horizontal track running under the ceiling. A cable passes through a movable pulley attached to the spring, then connects to the bottom of the door panel. When the door goes down, the spring stretches and stores energy. When it goes up, it shortens and assists with lifting.
This design is common on many residential doors. However, it requires depth along the tracks rather than height in the header. The key parts to monitor are the springs themselves, the pulleys, and the cables. You will find, for example, our extension spring compatible with Gypass, BKF, FAME, France Fermeture and our pulleys with spring hooks. Since the spring works in extension, a fall-arrest device (safety cable or parachute) is strongly recommended: see our article on the spring fall-arrest device.
Comparison: comfort, durability, space, and safety
In terms of comfort, the torsion spring generally offers smoother movement, while the extension spring is simpler in its design. For durability, everything depends on the quality of the wire and the number of cycles planned by the manufacturer: at equal quality, torsion often handles intensive use better. Space requirements also differ: torsion occupies the header, while extension occupies the sides along the tracks.
Regarding safety, both systems require caution. A breaking extension spring can project pieces of metal if not held back by a safety cable. A breaking torsion spring immobilizes the door and suddenly releases the accumulated tension. In both cases, never force the door. Furthermore, the choice between the two is not a personal preference at the time of replacement: it is dictated by the original design of your door.
Recognizing your system in three checks
First check: step onto a stable stepladder, with the door closed, and look above the door panel. If you see a horizontal metal shaft with one or two large springs wound around it, it is a torsion system. Second check: observe the horizontal tracks. Elongated springs above each track, connected to a pulley, indicate an extension system. Third check: examine the ends. The presence of cable-wound drums at each end of the shaft confirms torsion.
Also note the brand and year of the door, often indicated on a data plate placed on the frame or on a panel. This information will help you choose the right reference, as explained in our article on how to identify the brand of your sectional door. To help you choose from common brands, our Gypass, FAME, and SDA collections bring together compatible parts.
Can you switch from one system to another?
The question comes up often, especially when an extension spring breaks regularly. In practice, you do not switch from one system to the other by simply replacing a part. The change involves a shaft, drums, bearings, different cables, and a precise calculation of balancing based on the weight of the door. It is a modification of the installation that should be handled by a professional and is only justified in special cases.
In the vast majority of situations, the right approach is to replace it with an identical part, respecting the dimensions of the original spring. If you cannot find the exact reference, we manufacture custom torsion springs: consult our guide to order a custom spring.
Conclusion
Torsion spring above the door, extension spring along the tracks: the difference is noticeable at a glance and determines all compatible parts. Correctly identifying your system is the first step to a successful replacement and avoids ordering errors.
Keep in mind that both of these systems store a lot of energy: follow the safety instructions and, if in doubt, call a professional. Our team can help you validate a reference before you place your order.
FAQ: torsion or extension
Which system is most common on sectional garage doors?
Both are widely used. The choice depends on the manufacturer and the year of production. Only a visual check of your door allows you to know for sure.
Is an extension spring less durable than a torsion spring?
Not necessarily. Durability depends on the quality of the wire, the sizing of the spring relative to the door, and maintenance. Under equivalent use, torsion generally handles high numbers of cycles better.
Can I replace an extension spring with a torsion spring?
No, not by a simple exchange. Several elements must be changed (shaft, drums, cables) and the balance must be recalculated. This conversion must be entrusted to a professional.
How do I know which reference to order once my system is identified?
Note the dimensions of your spring, the brand and the year of the door, then compare with our product sheets. If in doubt, contact us with a photo: we will help you validate the right part.