When a sectional garage door becomes heavy, travels crookedly, or stops halfway, the spring is almost always the cause. Yet this discreet part does most of the work: without it, a door panel weighs several tens of kilograms that neither your arms nor a motor should have to lift alone, and its fall could be dangerous.
This comprehensive guide helps you understand the role of the spring, distinguish between the two main technologies, take the correct measurements, spot signs of fatigue, and order the right part, including custom-made ones. It serves as an entry point to our entire series on springs: each topic covered here is detailed in a dedicated article.
What is the purpose of a sectional garage door spring?
The spring ensures the door is balanced. It stores energy when the door descends and releases it when it rises, so that the door panel seems to weigh almost nothing. Thanks to it, a well-adjusted door remains stationary at any height and can be opened with one hand, even without motorization.
This balancing has two direct consequences. First, it protects the motor: an electric operator is not designed to carry the door; it only assists it. A tired or broken spring forces the motor, which accelerates wear on the gears and can trigger unintended stops. Second, it ensures safety: it is the spring, relayed by cables and drums, that holds the load. This is why a door should never be forced if a spring is broken.
Torsion spring or tension spring: two technologies to distinguish
Residential sectional doors use two families of springs. The torsion spring is mounted on a horizontal shaft located above the door, in the lintel. It twists when the door descends and transmits its force to the cables via the drums. There are generally two, one wound to the left and one wound to the right. The tension spring (or extension spring) is installed on each side, along the horizontal rails. It stretches when closing and contracts when opening, and is connected to the door by a set of cables and pulleys.
To find out which type you have, simply look above the door panel: a shaft with springs indicates torsion; springs stretched along the rails indicate tension. Each has its own reference vocabulary and associated parts. We detail the advantages, limitations, and identification marks in our article torsion or tension spring. For tension models, you can find, for example, our tension spring for sectional doors, compatible with several common brands.
The characteristics that define a spring
Two springs that look alike can have very different behaviors. For a torsion spring, four data points matter: the inner diameter, the wire diameter, the free length, and the winding direction, left or right. The number of coils is derived from these values. Additionally, the weight of the door and its height determine the force needed to balance it.
Being off by a few millimeters on the wire diameter or length is enough to cause the door to rise too quickly, fall back down, or put too much strain on the cables. The most reliable method is to measure the existing spring or, if it is broken, to measure the two sections as well as the wire using a caliper. We have taken the time to detail the step-by-step method in our guide taking measurements of your torsion springs. If your model is not in the catalog, custom manufacturing remains the best option, which we will address below.
Signs of a worn or broken spring
A spring that breaks makes a sharp noise, sometimes compared to a bang, which can be heard from inside the house. But wear often manifests before breakage. The door becomes heavier to lift by hand, rises jerkily, descends on its own halfway, or you notice a gap and a visible break between two coils of the spring. On a door with two torsion springs, only one may break: the door then leans to one side and the cables go slack.
In this case, the other spring has worked just as hard as the one that failed and is also nearing the end of its life. The most sensible approach is to replace both springs at the same time to restore balanced operation. We detail this point in the article dedicated to spring lifespan and replacement in pairs. And if your door is already broken, our article broken spring: what to do? provides the right responses.
Replacing your spring and ordering custom-made parts safely
A torsion spring is under high tension. Replacing it requires suitable tools, notably winding bars, and demands great rigor: never use screwdrivers or improvised wrenches, secure the door in the closed position before any work, wear safety goggles, and never stand in line with the bar during tensioning. If you have any doubt, entrust the task to a professional. Our spring winding bar is designed for this specific use.
Regarding orders, three situations arise. Your door is of a common brand: you can choose the compatible reference directly, for example with our spring compatible with Gypass, BKF, Safir, Lépinard, or the Gypass Europa spring and cable pack to renew everything at once. You cannot find the right reference: we manufacture custom springs to your specifications via the custom garage door spring form. Finally, to secure a door exposed to the risk of breakage, consider the spring safety device (parachute), which you will find in our safety and protection devices collection.
Conclusion
The spring is the centerpiece of your sectional door: it balances the panel, protects the motor, and determines the safety of the entire installation. Knowing how to recognize its technology, take its measurements precisely, and act at the first signs of fatigue avoids many breakdowns and emergency interventions.
At Mydoors, we distribute original parts from manufacturers and have been manufacturing custom springs in Hauts-de-France. To learn more, check out the articles in our series and, if in doubt about a reference, contact us before ordering: a verified measurement is better than returning a part.
FAQ: your questions about the sectional door spring
How do I know if my spring is a torsion or tension spring?
Look above the door. A horizontal shaft onto which one or two springs are wound indicates a torsion system. Long, thin springs installed on each side parallel to the rails indicate a tension system.
Should both springs be changed at the same time?
Yes, it is highly recommended. Both springs are the same age and work in the same way: if one has broken, the other will not be far behind. Replacing them as a pair ensures consistent balancing.
Can I order a custom spring if I don't know my door brand?
Yes. Simply take the spring measurements (inner diameter, wire diameter, length, winding direction) and the characteristics of the door. We will then manufacture the spring to those dimensions.
Can I replace a torsion spring myself?
It is technically possible for a skilled DIY enthusiast, with the right tools and by strictly following safety instructions. If in doubt, call a professional: the tension accumulated in the spring can cause serious injury.