Spring replacement is the garage door service most frequently done wrong — and the one with the most significant safety and performance consequences when it is. A spring sized incorrectly for the door’s actual weight causes the opener to overwork (shortening its lifespan), cables to wear unevenly, and the door to be off-balance. Understanding what correct spring replacement involves is the most protective thing a homeowner can know before hiring for this service.
“Every spring is specified to a door weight. If you don’t know the door weight, you can’t specify the spring correctly. It’s that simple. I see springs installed that are visually similar to the ones that broke — same color, roughly the same size — but specified for 50 pounds less than the actual door weight. The opener compensates by working harder. The cables wear faster. The door runs off-balance. None of that is visible until something else fails. Get the weight. Calculate the spring.”
— Kwame Asante, certified garage door technician and installer with 15 years of residential and commercial garage door experience in the local area
Table of Contents
Questions About Spring Types
What type of spring system does my door use?
Torsion springs:
Mounted horizontally on a shaft above the door opening. One spring for a single-car door; typically two for a double-car door. The spring winds and unwinds as the door operates, storing and releasing energy.
Advantages: More durable than extension springs, safer when they break (stays on the shaft), smoother operation, longer cycle life (typically 10,000–20,000 cycles).
Extension springs:
Mounted on either side of the door, above the horizontal tracks, running parallel to the tracks. Extend and contract as the door opens and closes.
Advantages: Less expensive to install. Disadvantages: Require safety cables threaded through them (without safety cables, a broken spring can become a dangerous flying projectile), shorter typical cycle life.
Ask which system your door has, and if you have extension springs, whether safety cables are present.
Questions About Spring Replacement
How will the correct spring specifications be determined?
This is the most important technical question in spring replacement. Spring specifications (wire diameter, inside diameter, length, and number of coils) are determined by:
Door weight: The primary driver. Springs are sized to the actual weight of the door — not an estimate, not a generic “standard residential door” assumption.
Door height: Taller doors require springs wound to a higher torque.
Cable drum size: The cable drum diameter affects the leverage calculation.
Desired cycle life: Springs with a higher cycle rating (20,000 cycles vs. 10,000 cycles) use heavier wire and are more expensive but last longer.
Ask specifically: how will you determine the correct spring specifications for my door? The answer should include either weighing the door or accessing the manufacturer’s exact weight specifications.
What a good answer looks like: “We’ll weigh the door with the spring at the bottom (disconnected from the opener) to get the actual door weight, then calculate the spring specifications based on that weight, your door height, and the cable drum size.”
A red flag: “We’ll replace it with the same spring that broke” or a flat price quoted without any information about the door — this suggests generic springs are being used without verification.
What is the cycle life rating of the replacement spring?
Springs are rated by expected cycle life — typically 10,000, 20,000, 30,000, or 50,000+ cycles. A cycle is one complete open-close operation.
At 4 uses per day, a 10,000-cycle spring lasts approximately 7 years. A 20,000-cycle spring lasts approximately 14 years.
Ask what cycle life rating the replacement spring carries and whether a higher-cycle spring is available at a premium. The upgrade is often less expensive than the difference in service call cost over the spring’s life.
Should both springs be replaced at the same time?
For double-car doors with two springs, if one spring breaks, the other is likely of similar age and similar remaining life. Replacing only the broken spring means the second spring will likely fail within months or years — at which point you’ll pay for another service call and another spring. Ask whether both springs should be replaced simultaneously.
What a good answer looks like: “Yes — the other spring is the same age and will likely fail soon. We recommend replacing both.”
Questions About Cable Repair
What caused the cable to fail, and is it related to the spring?
Cables that snap or jump off the drum are often a consequence of spring failure or improper spring tension — a door that’s too heavy for its spring will put excessive load on the cables. Ask the technician to assess whether the cable failure is a standalone issue or a symptom of a spring specification problem.
What cable material is being used?
Lifting cables are typically 7×19 galvanized aircraft cable — seven bundles of 19 individual wires each, for high strength and flexibility. Ask what cable specification is being used.
Safety: What Not to DIY
Torsion spring replacement is genuinely dangerous for an untrained person. A torsion spring under full wind tension stores enormous energy — enough to cause severe injury or death if the winding bar slips. Do not attempt spring replacement yourself without proper training, winding bars, and an understanding of the forces involved.
Extension spring replacement is slightly less dangerous but still requires safety cables, proper attachment, and tension setting.
Cable replacement on a door with a broken spring is manageable for an experienced DIYer in some cases — but only after the tension is fully released.
If in doubt: don’t. The service call cost is far less than the medical cost.
Related Questions
- Questions to Ask a Garage Door Contractor Before You Hire One
- Questions to Ask About Garage Door Openers and Safety Features
- Red Flags When Hiring a Garage Door Contractor
Have a question we didn’t cover? Submit it below.