Short answer. A torsion spring wire size chart turns a paint stripe into a wire diameter. DASMA Technical Data Sheet 171 lists every standard size from .1200 to .6250 inch, and commercial doors live in the top half of that table. The catch is that the colours repeat. Gold can mean .1770, .2500, .3310 or .4615. A tape and a set of calipers still decide the order.
This torsion spring wire size chart comes straight from DASMA. That's the door and operator manufacturers' association. Their Technical Data Sheet 171 sets the official paint colours that spring makers put on torsion and extension springs for sectional doors. It is the one page we check before anything else when a dock door spring snaps at six in the morning.
DASMA says plainly that the sheet is for manufacturers. It is not meant for building staff to pick a replacement. Spring replacement on a sectional door belongs to a trained door systems technician, and on a commercial door that goes double. These springs carry enough torque to break an arm or worse.
How to read a torsion spring wire size chart
The left column is wire diameter in inches. The right column is the paint colour the maker sprays on the spring or its cone. One colour, one diameter, for that row only. DASMA adds that colour gives partial identification. It says nothing about inside diameter or length. Stretch, material and finish aren't in it either, and they all change how much the spring lifts and how long it lives.
Spring paint fades. It gets painted over and it gets greasy. On older buildings in Richmond and Delta we often find no colour at all, or a colour that doesn't match what the calipers say. When the two disagree, the calipers win every time. Our torsion spring size page covers the 10 and 20 coil count method if you want to see how we measure.
The commercial end of the chart
Commercial sectionals are heavier than house doors, so their springs sit further down the table. Here is the part of the DASMA table we see most on commercial calls.
| Wire diameter (inch) | DASMA colour |
|---|---|
| .2500 | Gold |
| .2625 | Blue |
| .2730 | Orange |
| .2830 | Light Blue |
| .2890 | Yellow |
| .2950 | White |
| .3065 | Brown |
| .3125 | Tan |
| .3195 | Green |
| .3310 | Gold |
| .3437 | Blue |
| .3625 | Orange |
| .3750 | Light Blue |
| .3938 | Yellow |
| .4062 | White |
| .4375 | Tan |
| .5000 | Yellow |
| .5625 | Red |
| .6250 | Brown |
A spring marked black is unspecified or not on the list. That usually means a custom wire from the door maker. Treat it as unknown until it's measured.
Why the colours repeat
DASMA cycles the same ten or so colours down the table. Orange shows up at .1200, .1920, .2730, .3625 and .4844. Light blue at .1250, .2000, .2830, .3750 and .4900. So "it's an orange spring" narrows nothing on its own. A .2730 and a .3625 look nothing alike in your hand, but a facility manager on the phone can't tell us which one he's looking at from twelve feet away. We ask for a photo with a tape across ten coils, or we just come and measure.
What the hardware label and the door maker add
Every commercial door we install ships with a spring spec. Clopay's commercial installation manual says the springing information, including the number of turns, comes on the hardware box label. That label is the best record a building will ever have. Tape a photo of it inside the control box. When it's gone, we work back from the door weight and the drum, the same way the factory did.
The Clopay manual also flags that doors over 18 feet high, doors over 1,000 lb springing weight and doors on high cycle springs may need extra headroom and sideroom. Doors with more than one row of springs need more headroom again. Heavier wire means a longer and fatter spring. The shaft has to fit it.
Our rule on wire size
Here is our opinion, and we hold it hard. Never order a commercial spring off the paint colour. Measure every number on the spring every time, and confirm against the door weight. A wrong spring on a 600 lb door doesn't just wear out early. It changes the balance and loads the operator. It can also leave the door drifting down off the open stop, which DASMA's cycle life sheet calls out as a real hazard.
If a spring on your building is broken or looks stretched, stay away from the shaft and call us at (604) 206-5727. Winding is for trained techs with proper solid steel bars, full stop. Our commercial spring repair page explains how a service call runs, and signs a torsion spring is failing is worth a read before you call. For heavier wire on busy doors, see cycle ratings explained and our high cycle hardware upgrades. The oil tempered versus galvanized guide covers finish, which the colour code skips entirely.
