Garage door extension springs are made specifically for a door height. For example, extension springs for 7' high garage doors generally cannot be used with 8' doors. When you use an extension spring with a taller door, the spring will have to stretch farther to allow the door to close. This affects the lift of the springs as well as how long the spring will last.
Because of the pulley system, the extension spring's stretch is 1/2 of the door height. A common stretch for an 8' high door is 27X48. The 48 indicates that the difference between the spring length when the door is open and when it is closed is 48 inches. Two times 48 inches is 96 inches, which is 8 feet (the door height).
The other number indicated by the stretch of an extension spring is the spring length. In the example above, the 27 refers to a spring length of 27 inches when the spring is compressed. Though there are often multiple spring lengths for a given door height, longer springs tend to be used on taller garage doors.
Extension springs are also designed to lift a certain amount of weight. An 80-pound extension spring, for example, will lift 80 pounds. Because of the pulley system, however, it only lifts 40 pounds of door weight. The extension spring on the other side of the door will lift another 40 pounds. Therefore, two 80-pound extension springs are used on a garage door that weighs 80 pounds.
Garage door extension springs are also color-coded. The color for each spring can be found by viewing the detail when you click the part number or description. The lifts for extension springs follow these colors: Tan-100# - White-110# - Green-120# - Yellow-130# - Blue-140# - Red-150# - Brown-160# - Orange-170# - Gold-180# - Light Blue-190#. This pattern is repeated through all the lift categories. For example, a 90#, a 290#, a 390# and a 490# will all be painted light blue on one end.
Temporary fixes for broken ends. When the loop breaks off the end of an extension spring, there are two options for fixing the springs without replacing them. One is to separate the last two coils with a screwdriver and attach the s-hook or eye bolt.
The other temporary fix is to install a clip at the end of the spring. You can buy these at our hardware page linked below. Bear in mind that these are temporary fixes. You can expect your spring to break again at another place along the length or at the end of the spring. The best repair is to replace both or all four springs.
Springs for Off Applications. If you are looking for springs to use for a project other than for a garage door, you'll need to calculate the pull needed when the spring is fully extended. For example, if you want to ease the lift of a 300 pound object, you will need a spring that pulls 300 pounds when it is fully extended. A 25 inch spring that pulls 300 pounds on a 7 foot high door does not pull 300 pounds until it is stretched 42 inches beyond its original length of 25 inches. The total extended length of the spring would then be 67 inches. Here are two variations to consider. If you cut the 300 pound lift spring in half, it would pull 300 pounds when stretched only 21 inches. Or, if you pull the same 25 inch spring just 21 inches, it will pull only 150 pounds. If you determine what you need for your special application, we can usually find a solution.
The best way to determine the extension springs you need is to weigh your garage door. This video should help.
Additionally, in recent months, there has been a rising concern about the type of steel used in springs. For example, Chinese imported steel and springs are of a lower quality, and therefore much more brittle than other sources. At DDM Garage Doors, we make it our primary concern to not only help people figure out how to repair their garage doors, but also to provide excellent products for our customers. Therefore, if you purchase a spring from us, you can rest assured that all our springs are made with steel from the United States, thereby guaranteeing a higher quality than our competitors.
For extension spring cables, safety cables, pulleys, and other hardware for your extension spring door, see our Garage Door Extension Spring Hardware page.
Be sure that you replace all of the springs on your garage door. Replacing only one spring often causes an imbalance as the old spring has typically lost some tension. If just the loop on the end of your spring broke, consider purchasing just an extension spring clip on our extension spring hardware page. Installing the clip on the last two coils or so of the spring may allow the homeowner to continue using an old spring longer before needing to replace the springs.
Fill out the form below to find the extension springs that match your garage door. If you would rather browse our selection of springs, you can instead browse our catalog by garage door height and extension spring length. You may then also be able to choose your spring based on the type of spring end as pictured above.