Extension Spring Safety Cables: The Part Older Doors Are Missing

Extension springs are the long springs that stretch along the horizontal track on each side of the door, above the opening, on a lot of older and lighter garage doors. When the door closes, they stretch. When it opens, they contract and do the lifting.

When one breaks, all of that stored energy releases at once. Without anything to contain it, the broken spring whips across the garage with enough force to go through drywall, dent a car, or seriously injure anyone standing there. A safety cable is what stops that. It is a thin steel cable that runs through the middle of the spring, anchored at each end, so a broken spring is caught on the cable instead of flying.

How to check whether you have them

Go into the garage with the door closed and look up at the horizontal track on each side. You will see a long spring running roughly parallel to the track, from a bracket near the back of the track forward to a pulley. Look through the coils. If there is a cable running the length of the spring, through its center, you have safety cables. If the spring is open all the way through, you do not.

Check both sides. It is not unusual to find a cable on one side only, from a partial repair years ago.

If your door has springs mounted on a tube above the door opening rather than along the track, you have torsion springs, and this post does not apply. Our post on torsion versus extension springs explains the difference.

Why older doors do not have them

Safety cables have been standard practice on extension-spring doors for a long time, but plenty of doors were installed before that, and plenty more have had their springs replaced by someone who did not bother. Around Greene County we see doors from the 1980s and 1990s with no cables regularly, especially on detached garages and outbuildings where nobody has looked closely in years.

What installing them involves

This is one of the smallest jobs we do. Each cable anchors to the same rear bracket the spring hangs from, runs through the spring, over or past the pulley, and anchors at the front of the track. It has to be routed correctly so it does not bind the spring or the pulley, and it has to be the right length so it has a little slack when the spring is fully stretched.

Because the spring is under tension when the door is closed, the door should be open and secured, or the spring otherwise unloaded, when the cable is fitted. That is the part that makes it a job for someone who knows what they are doing, and it is why we do not describe it as a homeowner project even though the part itself is cheap.

We install safety cables as part of any extension-spring service, and as a standalone visit if that is all the door needs.

The rest of the extension-spring checklist

While we are at the springs, a few other things on an extension-spring door deserve a look.

• Matched springs. Extension springs are sold by the weight they lift, and the pair should match. Mismatched springs lift the door crooked.
• Pulleys. The sheaves wear and the bearings seize. A worn pulley chews the lift cable.
• Lift cables. Frayed strands near the bottom bracket are the warning sign. See our post on cable repair.
• Balance. With the opener disconnected, the door should stay put at waist height. If it drops or climbs, the springs are wrong or worn. Our balance test guide shows how.

Converting to torsion

If the springs are worn out anyway, converting an extension-spring door to a torsion system is worth considering. Torsion springs are contained on their tube by design, lift the door more evenly, and generally last longer. Whether it makes sense depends on the headroom above the door and the condition of the rest of it. Our post on converting extension to torsion covers the trade-offs.

Common questions

Is a missing safety cable an emergency? Not in the sense that the door will fail today. It is a hazard that exists every time the door cycles, and it is cheap to remove. We would get it done soon.

Can I install safety cables myself? The parts are inexpensive, but the springs are under tension and the routing matters. We recommend having them done with a spring service.

My door has one cable. Is that enough? No. Each spring needs its own.

Do torsion springs need safety cables? No. A torsion spring is mounted on a tube and stays there when it breaks.

Call (423) 262-3147 or request a free quote. Our spring repair page covers the service, and we check for safety cables on every extension-spring door we visit.