Garage Door Extension Springs

Garage door extension springs are installed along the horizontal track. Unlike torsion springs, extension or stretch springs fasten to a cable pulley system. As the garage door lowers the springs stretch out half of the door height.  When the door is closed the springs are under full tension, helping to raise the door on the way up.  These springs are typically used by the do-it-yourself homeowner since they are safer to install than standard torsion springs. They are also used in low headroom situations where there is not enough space for torsion springs to fit.



Since extension springs have to stretch during the loading phase and contract to help the door raise, length plays a major role in door operation. Extension springs for a 7ft tall garage door are a standard 25 inches and stretch 42 inches. Springs for an 8ft tall door are usually 28 inches and stretch 48 inches.


Extension Springs for 7 ft Tall Garage Doors (25-42)

 ColorWeightCycles/ LoopLength/ Weight
TAN100 lb25,000 Double Loop25-42-100
WHITE110 lb25,000 Double Loop25-42-110
GREEN120 lb25,000 Double Loop25-42-120
YELLOW130 lb25,000 Double Loop25-42-130
BLUE140 lb25,000 Double Loop25-42-140
RED150 lb25,000 Double Loop25-42-150


Extension Springs for 8 ft Tall Garage Doors (28-48)

 ColorWeightCycles/ LoopLength/ Weight
TAN100 lb25,000 Double Loop27-48-100
WHITE110 lb25,000 Double Loop27-48-110
GREEN120 lb25,000 Double Loop27-48-120
YELLOW130 lb25,000 Double Loop27-48-130
BLUE140 lb25,000 Double Loop27-48-140
RED150 lb25,000 Double Loop27-48-150


Inside Diameter

Inside diameter is a measurement of the width of the hollow space inside the spring. Most extension springs have small inside diameters of less than 2 inches. Inside diameter is more important when using torsion springs as opposed to extension springs. Springs with a larger inside diameter (ID) are used on heavier doors.

Wire Size

If all of the labeling is worn or rusted off your extension spring you will have to use your best judgement when matching springs. Examine the thickness of the springs by doing a 20 coil count. That means lay a tape measure over the spring and count 20 individual coils.  Do so on the spring you intend to purchase as well, making sure your length of 20 coils is identical on each spring.

End Type

The end loops of extension springs are made in three specific models. The three types of end loops are designed to support specific door weights. Light weight garage doors require single open loop ends, while heavier doors require double loop ends or clipped ends.

  • Singe Open Loop – Light Weight
  • Double Closed Loop – Mid Weight
  • Clipped End – Heaviest Weight


Finding Door Weight

If you aren’t able to match springs or have lost existing springs you will need to get a dead door weight measurement. To do this make sure all tension is off any springs connected to your garage door system. Use a standard bathroom scale to weigh your garage door. Use 3 pieces of wood on top of the scale if you are concerned about breaking it. Add about 5 lbs to the measurement you get and match your door weight to extension spring pull weight.


Replace Extension Springs in Pairs

Always replace extension springs in pairs. Not only will this save you time, but it will also save you money. Extension springs are rated for an estimated 20,000 cycles. If your springs were installed at the same time chances are the intact spring will break soon as well. Not replacing both could result in your garage door “stair stepping”  when in motion. This means the new spring is stronger than the older spring and pulls harder on one side. Replace all the extension springs on your garage door for smooth and quiet operation.

Garage Door Guide Cal
Hello, I’m Cal – owner of Garage Door Guide LLC    

I write tutorials about garage door repair, installation and maintenance. With over a decade of experience in the overhead door industry I’ve learned a lot and I’d like to share my knowledge with you.

2 thoughts on “Garage Door Extension Springs

  1. Mike Kunz says:

    Hi, this might be an unusual request. I have a 2006 enclosed toy hauler box trailer built by a company that went bust in 2009. They used garage door springs to help let the ramp down. I added two large pieces of thick wall rectangular tubing so it would support the weight of my Jeep when I drove up the ramp, which meant I needed more spring, so I picked up two at a big box store. It has worked satisfactorily until a few days ago when one of the original springs broke. It’s quite rusty and has no tags or markings, any paint is gone.
    They look to be the longer springs, I measured them and 27” seems like what a non-under-tension spring would be. I can’t take the other one off to measure or I won’t be able to open and close it.
    The ID is 1.5”, the coil count for ten coils is 40, the coils mic at 0.250, and they have a steel rod through center to contain them when they break.
    I don’t know the weight of the ramp door, but it’s heavy steel. Can you please help me find a replacement set?
    Thank you! Mike

    • psonline says:

      We carry 25″ relaxed (7ft tall doors) that stretch 42″ AND 30″ relaxed (8ft tall doors) that stretch 48″
      All springs work on a counterbalancing system where the pull force of the spring should equal the weight of the door being balanced. I don’t know much about ramp doors on a trailer, but I would imagine it works close to the same.

      You would need to find out how long the spring is fully stretched out and roughly how much the ramp weighs that you are trying to counterbalance.

      On our extensions springs the .250 wire size equals 240LB Blue or 260LB Brown…we don’t carry 250, 270, 290 (odd increments).

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