Calculating the spring size by the weight of my garage door

The first thing you need to do if you need to weigh your garage door is to find a scale that you would normally use to weigh yourself. Try to find a older scale that is not digital because sometimes if you add weight to a digital scale it will not give you the new reading it will just give you the original reading when weight was applied to the scale. The kind of scale I am talking about is one that has a dial and it spins back and forth when you step onto the scale. You will need a couple of things before you start to attempt to weigh your door the first is an assistant or somebody to help you read the scale as you are putting the full weight of the garage door on it. Other is a set of winding bars that a garage door technician would use to wined up the torsion springs.

Get a professional pair of winding bars

You will probably not find a professional pair of winding bars at a retail hardware store like Lowes or Home Depot so the next best thing is to go to a retail hardware store and buy 2 pieces of all thread that is 5 eighths of an inch thick and at least 18 inches long it would be better to have two bars but just to weigh the door most of the time you can get away with just one. Also you will most likely need a ladder to reach the torsion springs. Anytime I have had to weigh a garage door this is the procedure that I would use. The first step would be to open the garage door with the garage door opener if you have one if you do not have a garage door opener this does not apply. So once you have your winding bars your assistant to read the weight on the scale and your ladder it’s time to begin. If you have an opener and you have open the garage door with your garage door opener then you will need to pull down on the emergency release cord this is the red cord and handle that hangs down from the trolley on your opener real this allows you to open the door manually by hand. Will need to place the scale in the middle of the garage door and the window where you read the weight should be on the inside once the door is resting on the scale you will need to put the latter as close to the door as you can and stick your winding bars in the torsion spring cone on the ends of the springs there will be four holes total and what you will need to do is push up on the spring with the bar and look to your left or right at the cable drums where the cable wraps around the drum and once you see separation between the cable and the drum that the full weight of the garage door is on the scale and that’s when you take your reading of the weight.

how much your door weigh?

The next thing you will need is the height of the garage door. Measure the door height from the garage floor to the top of the top panel on your garage door and that will give you your height. Unless you are a mechanical engineer, the formula for determining this is pretty much like reading gibberish equations so if you need to let somebody know how much your door weigh and how tall it is for the correct spring this is the only information you should need. The best way to determine what spring to use is to measure the existing springs whether they are intact or broken to determine what size spring to replace. Once you have your IPPT (inch pounds per turn) there will be several different springs to choose from since combining different size springs can equal the right IPPT. For example: 2 inch diameter pair of yellow 0.207 x 23.75 inch springs have the same IPPT as one 0.250 x 30 inch torsion spring. This is why some 16×7 steel non-insulated garage doors will either have two torsion springs or one larger stronger spring to lift the same weight. The simplest way to explain this formula is
(Door Weight X Hi moment arm / Divided by # of turns = IPPT)