How to Measure and Order Torsion Springs
The torsion spring is an integral part of today’s garage door. It is a simple piece of mechanical hardware that uses a counterbalance assembly to offset the weight of the garage door. When the garage door is opened, the torsion springs unwind and the stored torque (energy) helps to lift the heavy garage door. As the door is closed, the torsion spring system winds up creating a storage of torque ready to be used when the door is opened again and the springs unwind. Each torsion spring is designed to last a certain amount of cycles with a cycle being one full opening and closing of the garage door or unwinding and winding of the spring. Once the spring reaches the designed life cycle, it could break. At this time, the torsion spring needs to be replaced by a professional garage door technician.
At SSC, manufacturing the correct torsion spring for your garage door repair or replacement is our most important job. From everyday stock springs to custom replacements springs, SSC offers the garage door spring that is right for you to complete your job.
The guidelines below will give you the information that is needed to order torsion springs from SSC.
DETERMINING THE SPRING WIND
One of the most commonly misunderstood facts about springs is the SPRING WIND – also known as wound. Spring wind refers to the direction the wire is coiled to make a spring. The wind is helpful to know the direction the spring will uncoil as the door moves up and down. The springs cones could have threads that match the spring’s wind or be universal in mounting.
In a normal garage door setup, a left-hand wound spring is mounted on the right side of the garage door and a right-hand wound spring is mounted on the left side of the garage door shaft. There are exceptions to this rule, but this is recommended for basic engineering.
Generally, the spring’s winding cones are color-coded to help you determine the springs’ wind. The cones on right-wound springs are colored red while left-wound springs are colored black. Sometimes these colors can be faded or non-existent so it is important to be able to determine the wind of a spring without the color coding.
Helpful Trick: Hold the end of the spring in your left hand. If the end coil follows the same direction from your fingertip to your thumb (Shaped like the letter C), you have a left wound spring. If it is opposite, you have a right wound spring.
FINDING THE LENGTH OF A TORSION OR EXTENSION SPRING
Possibly the most important step in measuring a garage door spring is to find the length. The length of a spring directly affects the springs winding capacity. For example, if you have a heavy garage door, you’ll need a spring that is large enough to lift the garage door. To find the length, first measure from spring end coil to spring end coil excluding the cones during the measurement of the torsion spring. Spring length measurements should be completed to the nearest quarter of an inch.
Special Notes: Torsion springs cannot be measured when they are active. A garage door that is open – even partially open – will stretch the spring larger and give you an inaccurate measurement. Even a spring that is ‘at rest’ but has been wound to the garage door will be stretched longer than the original size. A spring should be completely ‘unwound’ before measuring the length.
FINDING THE INSIDE DIAMETER (ID) OF A TORSION SPRING
The next step in measuring torsion springs is to determine the inside diameter (ID). With a tape measure or caliber, measure from inside spring coil to inside spring coil. The resulting measurement is the diameter of the spring. Measurements should be completed in inches and measured to 1/16” for accuracy.
If the spring you are measuring has spring fittings installed (cones or drums), you can verify the ID by looking for numbers that are etched into the hardware. For example, a 175 will be visible on spring fittings for 1-3/4” ID torsion springs. Generally, the torsion spring ID is a standard width. Refer to the chart below for a listing standard torsion spring inner diameters.
FINDING THE WIRE SIZE OF TORSION SPRINGS
The final step in measuring a garage door torsion spring is to determine the wire size of the garage door spring. Wire size can be measured by using a spring wire gauge, pocket wire gauge or a good ‘ole math formula. All three methods are simple and accurate at giving you the wire size of a torsion spring.
If you are using a spring wire gauge, insert the wire gauge into the spring and count twenty (20) coils. Once you have reached the twentieth coil, look at the numbered markings on the wire gauge to determine the wire size.
If you are using a pocket wire gauge, you can find the correct wire size by matching the correct coil key to your wire size.
If you don’t have a spring wire gauge or a pocket wire gauge, you can always use this trusted math formula to find the wire size of the torsion spring. To get started count 10 or 20 coils on the torsion spring. Measure the coils with your tape measure. Take the measurement and then divide by the number of coils you counted (10 or 20). The answer to the equation would be the wire size for the spring you just measured. Measure to the nearest 1/16 of an inch.
10 COIL EXAMPLE:
10 Coils = 2-7/8 (2.875) Inches
2.875 / 10 = 0.289 Wire Size
20 COIL EXAMPLE:
20 Coils = 5 Inches
5 / 20 = .250 Wire Size
You can also use the chart below to convert the length of coils into the wire size without doing the math.
SPRING WIRE CHART
| Length of 10 Coils | Length of 20 Coils | Wire Size |
|---|---|---|
| 1 1/4″ | 2 1/2″ | 0.125 |
| 1 3/8″ | 2 3/4″ | 0.135 |
| 1 7/16″ | 2 7/8″ | 0.142 |
| 1 1/2″ | 3″ | 0.1483 |
| 1 9/16″ | 3 1/8″ | 0.1562 |
| 1 5/8″ | 3 1/4″ | 0.162 |
| 1 11/16″ | 3 3/8″ | 0.170 |
| 1 3/4″ | 3 1/2″ | 0.177 |
| 1 7/8″ | 3 3/4″ | 0.1875 |
| 1 15/16″ | 3 7/8″ | 0.192 |
| 2 1/16″ | 4 1/8″ | 0.207 |
| 2 3/16″ | 4 3/8″ | 0.2187 |
| 2 1/4″ | 4 1/2″ | 0.2253 |
| 2 5/16 | 4 5/8″ | 0.2343 |
| 2 7/16″ | 4 7/8″ | 0.2437 |
| 2 1/2″ | 5″ | 0.250 |
| 2 5/8″ | 5 1/4″ | 0.2625 |
| 2 3/4″ | 5 1/2″ | 0.273 |
| 2 13/16″ | 5 5/8″ | 0.283 |
| 2 7/8″ | 5 3/4″ | 0.289 |
| 2 15/16″ | 5 7/8″ | 0.295 |
| 3 1/16″ | 6 1/8″ | 0.3065 |
| 3 1/8″ | 6 1/4″ | 0.3125 |
| 3 3/16″ | 6 3/8″ | 0.3195 |
| 3 5/16″ | 6 5/8″ | 0.331 |
| 3 7/16″ | 6 7/8″ | 0.3437 |
| 3 5/8″ | 7 1/4″ | 0.3625 |
| 3 3/4″ | 7 1/2″ | 0.375 |
| 3 15/16″ | 7 7/8″ | 0.3938 |
| 4 1/16″ | 8 1/8″ | 0.4062 |
| 4 7/32″ | 8 7/16″ | 0.4218 |
| 4 5/16″ | 8 5/8″ | 0.4305 |
| 4 3/8″ | 8 3/4″ | 0.4375 |
| 4 17/32″ | 9 1/16″ | 0.4375 |
| 4 5/8″ | 9 1/4″ | 0.4615 |
| 4 11/16″ | 9 3/8″ | 0.4687 |
| 4 7/8″ | 9 3/4″ | 0.490 |
| 5″ | 10″ | 0.500 |
| 5 5/16″ | 10 5/8″ | 0.5312 |
| 5 5/8″ | 11 1/4″ | 0.5625 |
| 6 1/4″ | 12 1/2″ | 0.625 |
ARE YOU VISUAL LEARNER? TRY SSC SOLUTIONS EDUCATION
SSC has spent more than 10 years developing an online video training platform to help professional garage door installers and dealers learn the in’s and out’s of the industry. Our INT05:Measuring a Spring Course includes the information above in an easy to follow instructional video followed by short quiz that can be submitted to IDEA for CEU credits. Additional instructional videos with a variety of topics including introductory courses, residential and commercial installations, customer service and management are all available for free to SSC customers.
TRY OUR SSC SPRING ENGINEERING APPS
SSC offers a smartphone app available for Apple & Android Devices and a Desktop App PC & Mac to assist you to quickly determine the garage door spring you need. Our engineering app help take out the the need to measure a spring. Simply put in a few pieces of information and the app will provide you with the size spring you need for the garage door you are working on. Our spring engineering app also offers additional tools to help you with a variety of garage door issues from determining the proper wind of the garage door spring to the cable length needed and more. Check it out today.
ORDERING TORSION SPRINGS FROM SSC:
When you reach out to SSC, you’ll need to have the following information on hand to ensure that your new springs are the correct size. Our sales team can assist you in determining if you can you a stock torsion spring size or if you’ll need a custom made torsion spring to meet your needs. The proper measurements of spring wind, length, inside diameter and wire size will help our sales team assist you in finding the torsion springs that you need.
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Safety Disclaimer: In order to see all procedures completely, there may be safety measures that are not taken by our actors. Be sure to follow any and all proper safety requirements and refer to your manufacturer’s installation manual for details. Your health and safety is the #1 concern. Failure to understand/follow the recommendations in the course could result in property damage, personal injury or death. While all efforts are made to provide accurate information and guidance, it is impossible to predict all door circumstances. Accordingly, the user agrees that the user of this video; products and information contained herein are at your own risk. In no event shall Service Spring be liable for any property damage, personal injury/death, or any other loss or damage that may result from your use of the information and products provided on this video. All information contained within this site is provided “as-is” without warranty expressed or implied. User assumes all responsibility/risk for use of information and products purchased. If you have any doubts about your ability to perform the work safely, we recommend you contact another door professional to complete your repair.
