Basic Spring Conversions

A basic operation carried out on-site is replacing garage door springs. To properly swap a damaged spring, the replacement must be as close to the dimensions of the original as possible. Accurately converting one spring’s dimensions to another is called spring conversion. Calculation of conversion is dependent on two factors: Inch Pounds Per Turn (IPPT) and maximum turns. Keep the IPPT of the replacement spring as close as possible to the original spring. The same rule applies to “maximum turns” as this makes swapping out the springs easier.

Let’s Use an Example
To paint a better picture of calculating spring conversions, here is an example that could occur in the field:

You are on call at a worksite. The customer needs one of their garage door springs replaced. The original spring is right-hand wound, 243 wire, 1 ¾ “ID, 32 inches long. The spring has an IPPT rate of 41.2 and is good for 8.1 maximum turns. On hand, you have some 250 wire springs with a 1 ¾” ID. With all of this laid out, how do we convert the original spring’s dimensions to match the new spring?

There are two main methods of conversion: through a rate book, or through an industry program.

What are the dimensions of my current torsion spring?

Every torsion spring has four dimensions: length, wire size, inside diameter, and wind. If you operated your garage door manually before your spring broke, it should have been fairly easy to open and close. If that’s the case, you can measure your old springs and then consider longer life options.

We hope this guide helps you to have a better understanding of the different types of wire used in the garage door industry and their purposes.

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