How to Choose the Correct Extension Spring
Determine Door Height: Make sure to order springs rated for your door height. The most common door height ratings are 7' and 8'. If you door height is a non-standard size, contact us for correct sizing..
Determine Door Weight: Extension springs are rated for the weight of door they will pick up. If the door weights 150 pounds, you will need a pair of 150# springs. To get a door weight,we use a bathroom scale set in the center of the door.With the springs removed, lower the door onto the scale. Keep in mind that the door will be very heavy and it should only be done with the help of several strong people. The color code that often is painted onto the end of the spring can also be used to help determine the correct spring size. Keep in mind that the color code repeats itself every 100 pounds (example: 100# and 200# will both be color coded tan)
Measure Spring Length: For Example; standard extension spring length for 8' high doors will be 27" without the loop or clips on the ends and will stretch 48" for total length of approximately 75" when door is fully closed. Extension springs for 8' doors also are available in 29" and 32" length by special order. (Contact us for pricing)