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One-Piece Curtain Door Torsion Springs

So you have torsion springs on a one-piece curtain door. To learn more about how your torsion spring system works, jump down to our Introduction to One-Piece Curtain Door Torsion Springs. The rest of this page is dedicated to helping you determine what torsion spring you need for your roll-up door.

Introduction to One-Piece Curtain Door Torsion Springs

One-piece curtain doors operate in a similar manner to steel-rolling door springs. Like a steel rolling door, the curtain on these doors wraps around itself as the door opens. The primary difference, however, is that steel rolling doors are made of interlocking slats, while one-piece curtain doors are just one piece of steel.

Some smaller one-piece curtain doors use only one torsion spring, while most larger doors use two torsion springs. Each torsion spring on the door typically has at least one turn when the door is fully open. This extra tension keeps the door open by restricting the curtain from unrolling off the drums.

As you close the door, each torsion spring winds up even more. This extra tension allows the springs to lift extra weight. The extra weight comes from a greater portion of the curtain hanging off of the drums.

When the door is fully closed, the springs have more turns (and thus tension) on them than at any other point in the door's travel. During the last six to twelve inches of travel, the moment arm (the distance from the center of the shaft to the point where the curtain rolls off the drum) is smaller than at any other time while the door closes.

The extra tension in the springs allows the springs to lift more door weight, namely the weight of the un-rolled portion of the curtain. The smaller moment arm, however, decreases the effective weight of the curtain. As a result, the springs lift extra door weight as the door approaches the floor, but the moment arm stays the same. Many times this causes the door to rise a few inches off the ground when you release the door at the bottom of its travel.

Determine What One-Piece Curtain Door Torsion Springs You Need

It is very important that you order the proper torsion springs for your one-piece curtain door. You will need to make several important measurements that must be accurate. If you are not careful when you make these measurements, your one-piece curtain door may not work as it did before.

Measure Your Old Torsion Springs

Measuring your old torsion springs is the most important part of ordering new springs. The information in this section is strictly informative and only gives an overview of how to measure your springs. For complete information, see our instructions for measuring torsion springs.

You need to make three measurements. The first is the spring length, which is the distance from one end of the spring to the other end. This is typically between 7 and 14 inches. The inside diameter is the distance across the inside of the spring. The 20-coil count is a measurement of the length of 20 coils on the spring. This measurement tells us the wire size.

You will also need to determine the wind of the spring. This will be either right or left, and it correspondes to the right or left side of the door when you are on the inside. You also need to verify that your spring has the mini-warehouse ends, as pictured on the left.

Replace One Spring or Both of the Springs?

If you have two springs on your one-piece curtain door, we generally recommened that you replace both of the springs on the door. Since each spring wears out at roughly the same rate, the secon spring on the door will probably wear out fairly quickly.

One-piece curtain doors are found in many self-storage locations. After one spring breaks, the second spring may have just 50 more cycles before it breaks as well. Depending on the usage of the door, this may be in a couple weeks, or it may be several years.

If you want to save money on service calls and time on repairs, replace both springs. If you want to save money on parts, just replace the broken spring.

How to Order

Once you have measured your spring, you can contact us with the following information:

1. Wire Size or 20-Coil Count
2. Length
3. Wind
4. Inside Diameter

Also mention that you have one-piece curtain door springs. With this information we can give you the pricing for your spring or springs. If you send us your zip code, we can calculate the shipping cost as well. We also provide quanity pricing breaks when you order at least 5, 10, 20, or 40 springs.