Frequently Asked Questions
The way to calculate the correct extension spring size for you door is to either know the color code on the end of your old springs or weight the door with bathroom scales when the door is not under spring tension.
- With the color code method remember the color code repeats every 100 lbs
- To weigh the door raise the door and use vise grips or a clamp in the track to hold the door up. Then take the other unbroken spring off. The vice grips will hold the door up. Take an analog bathroom scale and place it in the middle of when the door sits. Carefully remove the vise grips and lower the door onto the scale to get the weight. If it weighs 112 lbs then get a pair of white 110 lbs extension springs for your height door. If it weighs 115 to 120 lbs then round to green 120 lbs springs. (each spring lifts half of the door weight so a pair lifts what the rating is for.)
You really need 2 things to select the correct extension springs for your door. You will need to know the door height and weight. If you select the springs based on these 2 factor that is all you will need.
For explanation of the other numbers on extension springs.
Extension springs have specs based on the weight they lift as a pair and the heighth door they are meant to lift. They also have 2 sets of number like 25” x 42”. The first number 25’’ is the length of the extension spring when relaxed and not including the ends or loops. The second number tells you actually tells you what height door it is to be used for. The 42 inches is not stretch or anything it is half of the door height, so this spring is used for door up to 7ft tall (84”).
The best way to adjust your extension spring tension is to raise the door up and use a set of vise grips or a clamp in the track. On the track near the door opening you will adjust the length of the cable. Usually a tie off clip (3 hole metal piece that the cable is tied off to) and an S-hook, you usually can move the S-hook to a hole closer to the door opening to increase the spring tension or towards the spring to loosen the tension. Make sure you adjust both sides equally to make sure the door raises evenly and sits on the ground evenly.
You will raise the door and clamp or vise grip the door in the up position. Then the side that was high you can lengthen you cable length on the tie off clip or moving your S-hook to a hole away from the door opening. You also could do the opposite on the side that is lower. You could tighten the spring tension by shortening the cable on the tie off clip or move the S-hook closer to the door opening.
We advise to replace both springs that way the door opens evenly. Also we are big fans of changing all 4 pulleys. They are rated for 10000 cycles just like your springs and are extremely important on how smooth and quietly your door operates. If you don’t replace them now they will need it in the next year or two.
If your extension springs are not broke then you still need to check them for uneven gaps in the spring when the door is in the up position. This means they are stretched out and should be replaced. Also look at the hook or end loops to see if these are stretched or bending. Checking to see if the door will balance by manually lifting the door and check to see if it will stay half way up by itself and if it holds itself up when fully open. If it falls or raises on its own you my be able to adjust it enough to not need new springs. To make the adjustments see the questions above.
If it can’t be adjusted out then new springs are needed to make the door to function properly.