The main reason for learning how to measure torsion garage door springs is to order new ones. And that’s necessary when you want to replace them. So one small advice before explaining the way to measure springs: it’s wise to leave such projects to pros.
Any garage door spring repair can lead to accidents. Don’t forget that torsion springs are very heavy and wound – sometimes, even when they are broken. So, if you touch the setscrew of the winding cone or the bolts of the stationary cone, the spring might snap and hurt you.
It’s important to remember that in order to measure and/or replace springs, you need to come really close to them. And climb ladders or stools. Risky tasks!
And then it’s not easy to determine which torsion spring you’ve got in terms of brand and type – linear system? Duplex system? And some garage doors operate on two torsion springs in which case you need to measure them both.
One last thing. Torsion spring replacement is done with special tools. If you try to wind or unwind springs with simple ones, the job might not be done correctly. And you might injure your fingers. With that said, let’s move to one more critical thing.
Which precautions to take before you measure garage door springs
- Protect your face from the garage door spring by wearing goggles
- Put on gloves
- Make sure the ladder is stable
- Disconnect the garage door opener
- Keep the overhead door open (spring tension is released when the door is open)
- Place clamps to keep the door from sliding down
- Gather your tools around
How to measure torsion springs
What you need to know to order new garage door springs is the length, inside diameter, wire size, and wind type of the existing spring.
What you want to measure is the length of the unwound spring starting from the first
coil on one end to the last coil on the other end. Exclude the cones but include the coils on the cones. That’s relatively easy. The task becomes harder and more
dangerous when the spring is wound. In this case, remember NOT to touch the setscrews of the winding cone or the bolt of the stationary cone. The safest way to measure the length of the spring is to count the number of coils and then multiply that with the wire diameter. Now if the spring is broken, measure both pieces and remember not to touch the cones if the spring is wound.
Since this is the inner distance between coils, it’s hard to measure it if the spring is still on the shaft. To make your life easier, check if there is a sign on the cones. You might see the numbers ‘134’ or ‘175’ on the cones. These are the common inside diameters of standard residential garage doors.
This size indicates how thick coils are. You will need a caliper or measure tape. It’s often easier to use the tape to measure 10 or 20 coils. Then convert the number to a decimal but using a chart available online. For example, when the sum of measuring 10 coils is 2”, the wire size is 0.200.
While standing inside the garage, there is usually a left wound spring on the right hand side and a right wound spring on the left hand side of the door.