Quick answer
Spring wind direction is the direction a torsion spring’s coils spiral, left or right, which decides which side of the center bracket the spring mounts on and which way it must be wound.
On most two-spring residential doors, the right-wound spring sits left of center and the left-wound spring sits right of center, viewed from inside. DASMA lists winding a spring backwards as an installer safety hazard.
Quick facts
The key facts about Spring Wind Direction, with sources:
- Usual placement
- Right-wound on the left side, left-wound on the right (inside looking out) 5
- DASMA marking convention
- Red: left side, right wound. Black: right side, left wound 1
- Viewpoint terms
- LSLO and RSLO: left or right side looking out 1
- Wrong direction
- Winding backwards is a safety issue for the installer 3
- Who handles it
- A trained door systems technician 2
Key takeaways
- Torsion springs are made in left-wound and right-wound versions; they are not interchangeable.
- On a typical two-spring door, the right-wound spring is on the left and the left-wound on the right, seen from inside.
- Wind direction must match the side and the way the spring is tensioned.
- DASMA lists winding a spring backwards as a safety hazard for the installer.
- Identification and installation belong to a trained technician.
What wind direction means
Look along a coil spring and the wire spirals one of two ways, like the thread on a normal screw or a reverse-thread screw. A torsion spring wound one way is called right wound; the other is left wound. The two are mirror images.
Wind direction matters because a torsion spring only works when it is twisted to tighten its coils. Mount a spring on the wrong side, and turning the shaft to lift the door would unwind it instead of loading it.
DASMA’s spring guidance lists “winding a torsion spring backwards” as a potential safety issue for the installer, and says turns must always be applied in the direction the door maker specifies 3.
DASMA’s terminology even includes a marking convention: black marks parts as right side, left wound, and red marks parts as left side, right wound 1.
How wind direction pairs with door side
On a two-spring door, both springs sit on one shaft, anchored to a center bearing bracket in the middle. Each spring must tighten when the shaft turns as the door closes. Because the springs face opposite directions from the center, they need opposite winds.
DDM Garage Doors, a parts supplier, gives the standard layout: on most residential doors, the right-wind spring is on the left side above the door and the left-wind spring is on the right, as viewed from inside the garage 5.
Single-spring doors usually have one spring off to one side of a bracket; which wind it needs depends on which side it sits. Two-spring doors whose springs are not matched in size are a separate issue; DDM says many installers mix wire sizes, so each spring must be identified on its own 5.
Terms you will see
| Term | Meaning | Source |
|---|---|---|
| Right wound (RH) | Coils spiral one way; usually mounted left of center | DDM 5 |
| Left wound (LH) | Mirror image; usually mounted right of center | DDM 5 |
| LSLO | Left side looking out (from inside) 1 | DASMA |
| RSLO | Right side looking out 1 | DASMA |
| ISLO | Inside looking out 1 | DASMA |
| Winding cone | Part used to tension the spring 1 | DASMA |
Example: reading a spring line with wind
A quote that names wind direction alongside size. Format modeled on the five details a supplier asks for: length, wire size, inside diameter, wind and end type 5.
| Spring | Wire | Inside diameter | Length | Wind | Mounts |
|---|---|---|---|---|---|
| Spring A | .2253 | 2 in | 30 in | Right | Left of center bracket |
| Spring B | .2253 | 2 in | 30 in | Left | Right of center bracket |
- Each spring’s wind stated
- Wind matches the side
- Sizes stated for both springs
- Cycle rating stated
- Both springs replaced or reason given
Same size, opposite winds: that is a matched pair. If a quote lists two identical springs with the same wind for a two-spring door, ask why.
Where you see wind direction
On invoices and parts orders as “LH/RH,” “left wind/right wind,” or “L/R.” On some hardware, colored marks follow DASMA’s red and black convention 1. Some proprietary systems, such as Clopay’s EZ-SET, mark their winders R or L for the side of the door 5.
From the floor, you can often see which spring is on which side, but identifying the wind by looking closely at a wound spring means getting near stored energy. Leave that to a technician.
Why the two springs mirror each other
Picture the shaft as the axle both springs share. When the door closes, the cables unwind from the drums and turn the shaft one way.
Each spring is anchored at the center bracket by its stationary cone and fixed to the shaft at its outer end by its winding cone 1.
As the shaft turns, the outer end of each spring turns with it while the inner end stays still.
For both springs to tighten at the same time, the left spring and the right spring must spiral in opposite directions, because they extend away from the center in opposite directions.
That is the whole reason for left- and right-wound springs. It also explains why swapping them is not a small mistake: a reversed spring would loosen as the door closes and fight the other spring instead of helping it.
Single-spring doors follow the same logic. The one spring’s wind must match its side of the bracket so it tightens as the door closes.
Wind direction on enclosed and proprietary systems
Not every torsion system looks like a bare spring on a round bar.
Clopay’s EZ-SET system mounts springs to winders at the ends of the shaft, and DDM notes the black winder carries an R or L for the side of the door 5.
Wayne Dalton’s TorqueMaster puts one or two springs inside a steel tube; DASMA’s magazine described it in 1994 as the first counterbalance to seal springs safely within a steel tube 7.
These systems still use left- and right-handed parts, but they are matched to that system. Springs and winders from a standard setup will not drop into them. When a quote involves one of these systems, it should name the system and the side for each part.
One spring or two?
Many single-car doors use one torsion spring mounted to one side of a center bracket. Wider and heavier doors usually use two, one each side. DDM notes that two springs make a door safer if one breaks while the door is open, because the other can keep it from falling 5.
When a technician converts a one-spring door to two springs, the pair must be sized so their combined torque matches the door, and each must have the right wind for its side. That is a design change, not a simple swap, and it belongs with someone who can read the door maker’s chart.
Common wind mix-ups on service calls
Most wind problems happen at ordering time. A broken spring is described by phone, the wind is guessed, and the wrong part arrives. Suppliers ask for wind on every order for this reason 5.
Another mix-up is viewpoint. “Left” from the driveway is “right” from inside the garage. DASMA’s terms LSLO and RSLO, left and right side looking out, exist to remove that confusion 1.
A good quote states the viewpoint or uses those terms. If you describe a broken spring to a company, say which side it is on as you stand inside the garage facing the door.
Getting wind right vs wrong
What wind direction does not tell you
Wind direction says nothing about strength or life. Those come from wire size, inside diameter and length; see spring wire size. It also does not apply to extension springs, which stretch rather than twist 1.
Cost notes
No prices here; see the cost guide.
How a technician handles wind direction
Professional work only.
Records worth keeping
- Keep invoices listing each spring’s size and wind.
- Note which side each spring is on.
- Have both springs inspected at yearly service.
Why this is dangerous to DIY
Winding a spring the wrong way, or with the wrong tools, can release its stored energy suddenly. DASMA flags winding backwards and applying the wrong number of turns as installer safety issues 3 and says spring repairs and adjustments must be done by a trained technician 2.
Standards
No law sets wind direction. It is part of spring design under makers’ instructions and the voluntary ANSI/DASMA 103 counterbalance standard 6. DASMA’s TDS-160 records the red/black convention and the LSLO/RSLO terms 1.
Wind direction vs related terms
| Term | What it is |
|---|---|
| Wind direction | Which way the coils spiral |
| Winds on spring | Number of winding turns applied 1 |
| Spring torque | Twisting force the turns create |
| Torsion shaft | Bar both springs ride on |
| Torsion system | Springs, shaft, drums and cables together |
Myths about wind direction
- Myth Any torsion spring fits either side.
- Reality Left and right winds are mirror images and not interchangeable.
- Myth Wind affects how strong a spring is.
- Reality Strength comes from wire, ID and length.
- Myth It is easy to see the wind from the floor.
- Reality Close inspection means getting near a loaded spring; leave it to a pro.
Regional and brand differences
What to do with this
You do not need to identify wind yourself. Use it to read a quote: each spring should list its wind and match its side. Ask the technician to explain if anything looks off, and see what a spring repair involves.
Matched pairs have opposite winds
On a two-spring door, expect one left-wound and one right-wound spring of the same size.
Questions about Spring Wind Direction
What is spring wind direction?
The direction a torsion spring’s coils spiral, left or right. It decides which side of the center bracket the spring mounts on and which way it is wound.
Which side does a left-wound spring go on?
On most residential doors, the left-wound spring goes on the right side of the center bracket, viewed from inside the garage, and the right-wound spring on the left, according to DDM Garage Doors.
Are left and right torsion springs interchangeable?
No. They are mirror images. A spring on the wrong side would unwind instead of tighten as the door closes.
What do red and black marks on garage door parts mean?
DASMA’s convention uses red for left side, right wound, and black for right side, left wound.
What does LSLO mean?
Left side looking out: the left side of the door as seen from inside the garage. RSLO is the right side looking out.
Is winding a spring backwards dangerous?
Yes. DASMA lists winding a torsion spring backwards as a safety issue for the installer. Turns must go in the direction the door maker specifies.
Do extension springs have a wind direction?
Wind direction matters for torsion springs, which twist. Extension springs stretch along the tracks and are sized by door weight instead.
Should I check my spring’s wind myself?
No. Checking closely means getting near a wound spring. A technician identifies wind when sizing replacements.
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 #190, Factors Affecting Spring Cycle Life, retrieved .
- DASMA Technical Data Sheet #369, Frequently Asked Questions Regarding Automated Residential Garage Door Systems, retrieved .
- DDM Garage Doors (parts supplier), Garage Door Springs: types, measuring and FAQs, retrieved .
- DASMA, The New DASMA 103 (interview on the counterbalance standard, Door & Access Systems, Winter 1999), retrieved .
- DASMA, “10 Years Ago: Anti-Codegrabbing Technology Announced” (Door & Access Systems, Fall 2004), 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: Terminology and color convention from DASMA TDS-160; safety from TDS-167 and 190; placement and ordering details from DDM Garage Doors; standard from DASMA’s DASMA 103 article.
Suggest a correction. We fix errors and say what changed.