Quick answer
A garage door lift cable is the braided steel wire rope that connects the door’s bottom corners to the spring system, carrying the springs’ lifting force to the door as it opens and closes.
On torsion doors the cables wind onto drums at each end of the shaft; on extension doors they run over pulleys. DASMA calls the material aircraft-type cable: several strands of galvanized wire rope braided together.
Quick facts
The key facts about Lift Cable, with sources:
Key takeaways
- Two steel cables, one per side, carry the springs’ force to the bottom of the door.
- They are always under tension, even with the door closed.
- A frayed, slack or broken cable can let a door tilt, jam or fall.
- The bottom brackets the cables attach to are under extreme tension.
- Cable replacement is technician-only work.
What a lift cable is
Springs store the energy that lifts a garage door, but they sit above or beside the door. The cables carry that energy down to the door itself. There is one cable on each side, attached to a bottom bracket at the lowest corner of the door.
DASMA’s terminology names the material aircraft-type cable, defined as several strands of galvanized wire rope braided together 1.
It lists related parts: a cable stop, the swaged fitting on the cable end that keeps it from slipping through the drum slot, and cable length, the specific amount needed to operate the door properly 1.
On torsion systems, each cable winds onto a grooved cable drum at the end of the shaft. On extension systems, the cable runs up and over pulleys to the spring 1.
How cables lift the door
On a torsion door, the springs turn the shaft, the shaft turns the drums, and the drums wind the cables on, pulling up on the bottom brackets. Because both drums sit on the same shaft, both cables wind at the same rate and the door rises level.
Cable tension is what keeps the cables in the drum grooves. On standard-lift track, the door’s weight keeps the cables taut.
DASMA warns that with a wall-mount (jackshaft) opener, cable tension is lowest when the door is open, and without the door maker’s provisions the cables can go slack and come off the drums, leading to uncontrolled door movement, severe injury or death 7.
Some bottom brackets include a broken cable device, which DASMA defines as a bottom fixture intended to prevent the door from falling if a cable breaks 1.
- SpringStores the door’s weight as torque 1
- ShaftCarries the torque 1
- DrumWinds the cable 1
- CableBraided galvanized wire rope 1
- Bottom bracketLifts the door from its lowest corner 1
Source: [1]
Cable setups
| Setup | Where the cable runs | Source |
|---|---|---|
| Torsion, inside hook-up | Between the door sections and the vertical track | DASMA 1 |
| Torsion, outside hook-up | Outside the tracks | DASMA 1 |
| Extension springs | Over pulleys (sheaves) to the springs | DASMA 1 |
| Center lift cable | Extra cable toward the door’s center on very wide or heavy doors | DASMA 1 |
| Containment cable | Through an extension spring; does not lift | DASMA 1 |
Example: what DASMA’s checks look for
Cable items from DASMA’s home inspector checklist and post-storm occupant guide 2 4.
| Check | What to look for | Source |
|---|---|---|
| Spring system | Loose cables or loosened parts; do not touch | TDS-174 4 |
| Bottom brackets | Two warning labels near them (unless tamper-resistant) | TDS-167 2 |
| Hardware | All parts secure and damage-free | TDS-167 2 |
| Operation | Rollers stay in track; door does not open faster than force applied | TDS-167 2 |
- Frayed or broken strands
- Cable slack on one side
- Cable off the drum grooves
- Door hanging crooked
- Rust along the cable
- Bottom bracket bent or loose
These are look-only checks. DASMA says occupants should not touch springs or anything they are fastened to, including cables and brackets 4.
Where to find the cables
Follow the edge of the door down to the bottom corner on the inside. The bottom bracket holds the cable end. From there the cable runs up beside the vertical track to the drum on the end of the shaft (torsion) or to a pulley near the front of the horizontal track (extension).
Look but do not touch. DASMA’s labels include one warning that the bottom bracket is under extreme spring tension 3.
Why cables fail
Cables wear where they bend and rub: on the drum grooves, over pulleys and where they enter the bottom bracket. Rust is the other enemy, especially at the bottom bracket near a wet floor or in coastal air. DASMA notes coastal and saline conditions shorten spring life 5; the same moisture attacks cable strands.
Cables also fail after something else goes wrong: a broken spring that lets one side drop, a door that binds and goes slack on one side, or a jackshaft opener without tension provisions 7. When a cable jumps off its drum, it often frays or kinks.
Cable length and a level door
Both cables must be the same working length for the door to sit level.
If one side is shorter, that corner lifts first and the door rises crooked; if one side is slack, that corner lags and the door can jam in the track.
DASMA defines cable length as the specific amount of cable required to properly operate the door 1, and lists cable drum set screws, one of which may secure the cable to the drum to hold the right length 1.
A level door also matters for safety. DASMA says the door must be level to the floor, because gaps keep the opener’s reversal system from working properly across the width 6. A door that closes with one corner up is a door whose reversal may not trigger on that side.
Inside and outside hook-up
Where the cable runs relative to the track depends on the bottom bracket design. DASMA describes inside hook-up, where the cable runs between the door sections and the vertical track, and outside hook-up, where it runs outside the tracks 1. The bottom bracket is made for one or the other.
The difference matters on service calls: replacement brackets and cables must match the original hook-up, and a cable routed the wrong way can rub the track or the door edge.
Cables on high-lift and vertical-lift doors
High-lift and vertical-lift doors travel farther up the wall, so they need longer cables and special drums.
DASMA lists a high-lift drum, contoured to balance a high-lift door, and a vertical-lift drum, with changing radius grooves to match spring tension 1.
These setups are less forgiving of slack and wear, and the cable path should be checked at every service visit. See high-lift track.
If a cable has come off the drum
A cable off its drum means the door is no longer held evenly. The spring may still be wound, and the door can shift suddenly if moved.
Leave it where it is, do not run the opener, unplug the opener if you can do so away from the door, and keep everyone out of the garage door area until a technician arrives.
Healthy cables vs worn cables
Healthy cables
- Door rises level and stops evenly.
- Cables sit snug in the drum grooves.
- No broken strands or rust.
Worn cables
- Door tilts or jams in the track.
- Cable can snap, letting one side drop.
- Slack cable can unwind from the drum 7.
What a cable cannot do
A cable only transmits force. It cannot make up for a weak spring or a heavy door; those are spring problems. And it cannot stay in its groove if it goes slack, which is why DASMA’s jackshaft guidance focuses on keeping cables tight 7.
What drives cable repair cost
No prices here; see the cost guide.
- Both cables at once, so they match in length and wear.
- Drums if grooves are damaged.
- Bottom brackets if rusted or bent.
- Springs if a spring failure caused the cable problem.
- Door damage from a drop or jam.
How a technician replaces cables
Professional work: the spring tension must be safely released first.
- Secures the door and releases spring tension with proper tools.
- Replaces both cables with the correct length for the door 1.
- Seats each cable stop in its drum slot and sets equal tension on both sides.
- Re-tensions the springs per the maker’s instructions 5.
- Checks that the door rises level and balances 2.
- Tests reversal if an opener is fitted 6.
Owner checks
- Look at both cables from the floor every few months.
- Keep the bottom corners dry; clear standing water.
- Watch for the door rising crooked.
- Never lubricate or touch cables yourself; book yearly service.
Danger signs
A loud snap, a door hanging lower on one side, a cable dangling loose, or a door stuck crooked in its tracks. Do not run the opener and do not try to force the door. DASMA says to stop and contact a trained technician if any problem is seen 4.
Standards
Under the voluntary ANSI/DASMA 103 counterbalance standard, removable parts under tension, including corner (bottom) brackets, must be non-removable under tension, need special tools, or be red with warning labels 8. DASMA’s label set includes a bottom bracket safety label 3.
Lift cable vs related parts
| Part | Job |
|---|---|
| Lift cable | Carries spring force to the door |
| Cable drum | Winds the cable on torsion doors 1 |
| Containment cable | Retains a broken extension spring 1 |
| Torsion shaft | Carries spring torque to the drums 1 |
| Bottom bracket | Holds the cable end and lower rollers 1 |
Myths about cables
Climate notes
Coastal salt air and wet floors rust cables fastest at the bottom brackets. DASMA links saline coastal conditions to shorter spring life 5; inspect cables more often in those places.
What to do
If you see fraying, slack or a crooked door, stop using it and call a technician. Ask whether springs and drums should be checked at the same visit. See door repair.
Replace in pairs
Ask for both cables to be replaced together; matched cables keep the door rising level.
Questions about Lift Cable
What do garage door cables do?
They carry the springs’ lifting force to the door’s bottom corners. On torsion doors they wind onto drums; on extension doors they run over pulleys.
Why did my garage door cable come off?
Usually because it went slack: a broken spring, a door that bound in its track, or a wall-mount opener without tension provisions. Park the door and call a technician.
Can I replace garage door cables myself?
No. Cables and bottom brackets hold the springs’ full force. DASMA says adjustments to springs, cables and brackets must be made by a trained technician.
What happens if a garage door cable breaks?
One side can drop, the door can jam crooked, and the other side carries extra load. Do not run the opener; keep people clear.
What kind of cable do garage doors use?
DASMA calls it aircraft-type cable: several strands of galvanized wire rope braided together.
Should both cables be replaced?
Yes, typically. Matched length and wear keep the door level.
Why is my garage door crooked?
A frayed, slipped or broken cable, or a broken spring on one side, are common causes. Stop and call a technician.
How long do garage door cables last?
There is no fixed life. Cables wear where they bend over drums or pulleys and rust where they meet a wet floor. Have them inspected at yearly service and replaced if strands are broken or rusted.
Does a wall-mount opener affect the cables?
It can. DASMA warns that on standard-lift track, a jackshaft opener needs the door maker’s provisions to keep cables taut, because slack cables can come off the drums and cause uncontrolled door movement.
Are bottom brackets dangerous?
Yes. DASMA labels warn that the bottom bracket is under extreme spring tension. Do not loosen it.
Sources
- DASMA Technical Data Sheet #160, Sectional Garage Door Terminology, retrieved .
- DASMA Technical Data Sheet #167, Residential Sectional Garage Door and Electric Operator Checklist for Home Inspectors and Consumers, retrieved .
- DASMA Technical Data Sheet #172, Garage Door Labels, retrieved .
- DASMA Technical Data Sheet #174, Building Occupant: Checking a Residential Sectional Garage Door for Damage, retrieved .
- DASMA Technical Data Sheet #190, Factors Affecting Spring Cycle Life, retrieved .
- DASMA Technical Data Sheet #369, Frequently Asked Questions Regarding Automated Residential Garage Door Systems, retrieved .
- DASMA Technical Data Sheet #1501, Standard Lift Garage Doors with Jackshaft Operation, retrieved .
- DASMA, The New DASMA 103 (interview on the counterbalance standard, Door & Access Systems, Winter 1999), retrieved .
Expert review
Written by the HyreGarage Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Definitions from DASMA TDS-160; inspection items from TDS-167 and 174; labels from TDS-172; cable tension warning from TDS-1501; standard from DASMA’s DASMA 103 article.
Suggest a correction. We fix errors and say what changed.