How to Know What Springs to Buy for Your Garage Door
Five measurements from your old springs, or just the weight of your door. Either way you end up with the exact sizes to order.
Short answer
To know which torsion springs to buy, measure the old spring's wire size (10 coils divided by 10), inside diameter and length of the coils, and note whether it is left or right wound. Check those sizes in a spring calculator against your door's height. If the old springs are broken, missing or were never right, size new ones from the door's weight instead. Replace both springs together.
Method 1: measure your old springs
This is the quickest way when the door balanced well before a spring broke. You need a tape measure and five minutes. Do not loosen or unwind anything to take these measurements.
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1
Check that you have torsion springs
Torsion springs sit on a steel bar above the door, with a cable drum at each end. Springs that run along the horizontal tracks on each side are extension springs, which are sized differently and are not covered here.
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2
Measure the wire size
Measure the length of 10 coils pressed together and divide by 10. Ten coils measuring 2 1/4" is a .225 wire. Measuring 20 coils is even more accurate. The wire size guide has a chart for every common size.
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3
Measure the inside diameter
Most home garage door springs are 1 3/4" or 2" inside diameter. Heavier doors can use 2 1/2" or 2 5/8". Measure across the inside of the coil, or read the size stamped on the winding cone if it has one. See the inside diameter guide.
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4
Measure the length of the coils
Measure the coils only, not the cones at each end. Measure the broken spring if you can: it has let go of its tension. A spring that is still wound grows longer as it is wound, so it measures long. Push the two broken pieces together and measure them as one. See the spring length guide.
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5
Note which way each spring is wound
Springs come left wound and right wound. On a door with two springs, seen from inside the garage, the spring to the left of the center bracket is right wound and the spring to the right is left wound. Order the same wind you take off.
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6
Check the size before you order
Enter the wire size, inside diameter and length with your door height in the garage door spring calculator. Add the lifting capacity of all the springs together: it should be close to the weight of the door. The calculator also shows how many turns to wind and how long the springs should last.
Method 2: start from the door's weight
Use this when the old springs are missing, broken beyond measuring, or were the wrong size to begin with. Wrong springs show up as a door that drifts up on its own or feels heavy and drops.
- Find the door's weight with the garage door weight calculator, which estimates it from the size, material and model.
- Measure the door's width and height, and find the track radius.
- Enter everything in the spring size calculator by door weight. It lists springs that balance the door, with the cycle life you choose.
What to write on the order
Spring suppliers list torsion springs as wire size x inside diameter x length, plus the wind. For a two-spring door that looks like:
1 x .225 x 2" x 25" right wound
New springs normally come with their winding and stationary cones fitted. Choose the cycle life too: 10,000 cycles is standard, and higher-cycle springs use thicker wire and a longer spring for the same door.
Safety
A wound torsion spring holds enough energy to cause serious injury. Wind springs only with proper winding bars, never with screwdrivers or other tools, and never loosen the set screws on a wound spring. If you are not trained for this work, have a garage door technician install your springs.