Reference
Garage Door Glossary
Plain-English definitions for garage door terms used across our Learn hub, service pages, and homeowner estimates, so you and our technicians use the same words for the same parts.
How to use this glossary
Use these definitions to decode estimates, understand what's on a technician's invoice, and follow our Learn guides without getting lost in jargon. Every term links to the related guides and services so you can move from terminology to a real decision.
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Decode the estimate
Look up any unfamiliar term on a service invoice or a written quote.
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Move to a guide
Each term links to the Learn guides that go deeper on the same topic.
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Garage Door Terms
16 canonical definitions
The terms used across our service pages, Learn guides, and homeowner estimates, defined once, in plain English, for Nashville and Middle Tennessee homeowners.
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Garage Doors
Torsion spring
A torsion spring is the tightly wound coil mounted on a horizontal shaft above the garage door opening. It stores rotational energy as the door closes and releases it to counterbalance the door's weight on the way up. Almost every residential garage door installed in the last 25 years uses torsion springs.
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Garage Doors
Extension spring
Extension springs are long, narrow coils mounted parallel to the horizontal tracks on each side of the garage door. They stretch as the door closes and contract to help lift it on the way up. Common on older garage doors but largely replaced by torsion springs on new installs.
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Garage Doors
Cycle rating
A cycle is one complete open-and-close of the garage door. Cycle rating is the number of cycles a torsion spring is engineered to handle before metal fatigue causes it to break. Standard residential springs are rated around 10,000 cycles, typically 3–10 years of use depending on daily cycle count.
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Garage Doors
Garage door opener
A garage door opener is the motorized unit mounted on the garage ceiling that drives the door up and down. The opener doesn't lift the door's weight, the springs do that. The opener provides the small amount of force needed to start motion and to hold the door at the open position.
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Garage Doors
Belt drive opener
A belt drive opener uses a reinforced rubber belt to move the trolley along the opener rail. Belt drives are dramatically quieter than chain drives and are the right choice for any garage that shares a wall or floor with a bedroom or living space.
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Garage Doors
Chain drive opener
A chain drive opener uses a metal bicycle-style chain to move the trolley along the opener rail. Chain drives are the cheapest opener type, mechanically simple, and just as durable as belt drives, but they're noticeably louder and transmit more vibration through the ceiling structure.
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Garage Doors
Photo-eye sensors
Photo-eye sensors are the small infrared transmitter-and-receiver pair mounted on either side of the garage door opening, roughly six inches off the floor. They project a continuous beam across the doorway; if anything breaks the beam while the door is closing, the opener reverses immediately. They are federally required on every residential garage door operator manufactured since 1993.
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Garage Doors
Safety reverse
Safety reverse is the federally required feature on a garage door opener that causes the closing door to stop and reverse to fully open when it encounters resistance or when the photo-eye sensor beam is broken. UL 325 specifies how this must be tested and at what force threshold.
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Garage Doors
Force limit setting
The force limit setting on a garage door opener is the adjustable threshold of resistance at which the opener will stop and reverse. UL 325 requires every residential opener to ship with adjustable up-force and down-force limits, and they must be set during installation so the door reverses on a 1.5-inch obstruction.
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Garage Doors
Lift cables
Lift cables are the two braided steel cables that run from the bottom corners of the garage door up to drums mounted on the torsion spring shaft. They transfer the spring's stored energy to the door's weight. Cables are sized to the door's weight and should always be replaced as a matched pair.
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Garage Doors
Rollers
Rollers are the small wheels mounted along each side of the garage door that ride inside the vertical and horizontal tracks. Common roller types are nylon (quiet, longer-lasting) and steel (cheaper, louder). Residential rollers typically last 5–10 years depending on use and lubrication.
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Garage Doors
Track
The track is the metal channel, vertical along the door frame and horizontal across the garage ceiling, that the rollers ride inside as the garage door opens and closes. Tracks bend, dent, and develop debris build-up; any of those will make the door bind or pop off-track.
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Garage Doors
Off-track door
An off-track garage door is one where one or more rollers have come out of the metal track. It usually happens when a broken cable, broken roller, or impact (a backed-up car) lets the door geometry collapse. An off-track door is an immediate safety hazard, stop using the opener and call for emergency service.
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Garage Doors
Balance test
A balance test confirms that the garage door's springs are sized correctly for its weight. With the opener disconnected, the door should stay roughly in place when released at the half-open position. If it drops or shoots up, the springs are out of balance and the opener is doing work it shouldn't be.
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Garage Doors
Weather seal
Weather seals are the rubber or vinyl strips around the perimeter of a garage door that block air, water, dust, and pests from entering the garage. The bottom seal (astragal) takes the most abuse from concrete contact and weathering and typically needs replacement every 3–7 years in Middle Tennessee.
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Multi-trade
UL 325
UL 325 is the Underwriters Laboratories Standard for Door, Drapery, Gate, Louver, and Window Operators and Systems. It defines the entrapment-protection requirements, photo-eye sensors, force limits, and manual disconnects, that every residential garage door operator sold in the U.S. since 1993 must meet under federal CPSC mandate (16 CFR Part 1211).
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Reviewed and kept current
- ✓ Definitions checked against UL 325, CPSC 16 CFR Part 1211, and DASMA technical standards.
- ✓ Locality notes drawn from in-the-field service across Middle and East Tennessee.
- ✓ Updated whenever parts, products, or safety codes change, last updated June 2026.
- ✓ No invented code sections, no fabricated certifications, sources cited where they exist.
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