Selecting the correct springs for your garage door is an absolutely critical part of a successful spring replacement.  You must use springs that are the correct strength for your door or it will not work reliably.  If your springs are too weak, your garage door will be heavy and want to slam down hard.  This puts lots of unnecessary wear and tear on the opener, creates a dangerous situation, and leads to malfunctions that can be expensive to fix.  If your springs are too strong, your door will fly open by itself, leading to all the same problems in reverse.

If everything had been working well for a long time before the spring broke, you may be able to find the exact same springs available to purchase and everything will be fine.  But if you have been going through springs quicker than you should, or your opener force settings have to be turned way up to make it work, or your opener has a stripped gear or trolley, you may have had the wrong springs on your door.

The weight of your door is what really affects the springs you need.  Height is a factor too, but as long as your door is between 6′ and 9′ tall you don’t really need to worry about it when selecting a spring.

Changing the length of a spring has a major impact on its strength (shorter = stronger).  For example, if your door had a 1.75″ inside diameter spring made of .250 guage wire and 39″ long, you CANNOT use a 1.75″ x .250 x 35″ in its place as the later is 10% stronger meaning your door will want to fly open on its own.

As a rule of thumb, you can get away with using a spring of equal inside diameter and wire size that is up to 2 ippt lower (you can add up to one extra turn to the spring if needed) or 1 ippt higher (you CANNOT under-wind the springs or the cables will come off when the door is fully opened) than the correct spring.

Consult this spring strength guide to double check your springs before ordering.  If you end up with the wrong springs for you door it will be impossible to successfully fix your door.

Here is a general chart to tell you the ballpark strength of the springs you need for your door.  Be sure that whatever you select jives with this chart.

Door Type
(this chart applies to doors up to 9' tall)		WidthIPPT
Non-insulated Steel1640-50

*upto 55 for heavy duty non-insulated
9, 8
20-26
Insulated Steel Vinyl Back1650-60
9, 825-30
Insulated Steel Back1660-70
9, 830-40
Wood doors, thin recessed panel1660-75
9, 830-40
Wood doors, raised panel1685-100
9, 840-50