Garage Door Springs


Most extensional springs are not always built with probable door measurements in mind and they come with the following distinguishing hallmarks;



finishing type.

wire size.

Most manufacturers come with their own spring prototypes and therefore weight becomes an important criterion for distinction whilst the general practice is to manufacture springs for domestic usage to 10 lb and its increments. For heavier industrial usage, the preferred weight is 20 lb and upwards.

The wiring is on the still pulley, and as it attaches on to the extension spring; it makes a steady connection with the track with a wiring holder, and an S-hook.

The height of the door plays a crucial part in the choice of the use of an extension spring. Considering a 72” (6 feet) tall door, the spring has to be at least 36” longer than its normal length when un-stretched. Irrespective of the variation, its measurement must be equal to half the height of the door. The in-built pulley system works like this – as the door opens 2’ from the ground, the wiring attaching it to the bottom template is also raised by 2’. The wiring, encircling the still pulley, latches on to the second one. The cable goes around and is hooked to the track with a wire clip and s-hook.

A pulley fork connects the 2nd pulley with the spring. 2’ of cable going around this pulley shall require 1’ of the wiring to be increased from the S-hook. The spring too shall get decreased by 1’, thus preserving the cable’s tautness. It is seen that the range of the stretch of the spring is half of the height of the door.

Defining Extension Spring Mechanism

They can be used on both the sides of the door. Usually, it is one on either side, but sometimes more than one are used. This system of springs lifts the door. Over time, the springs are used on both sides; each side lifts half the door-weight. This ensures a perfect working sync for the two coils of the spring.

DFinding the right Extension Spring

In order to have a perfectly functioning garage door, you must replace your worn-out springs with new ones which match evenly with the door weight. Worn out springs occasionally break pulleys, and cables; safety precautions here are necessary; change the part before calamity strikes.

How to measure right

One vital thing to know is the door’s weight and height, and the spring’s length to order the right spring for the garage door.

The scale should be put under that side of the door with a broken spring. The calculating bit can be dicey, and it is advisable to use analog scales over digital ones. If two extension springs are broken, the scale should be placed under the central bottom of the door whereas if, on the other hand, one is found to be faulty, the scale should be under the door with the faulty spring.

The door, as well as the rollers, must be shaken. At any time, any spring gets broken, and then the weight on the scale should be of half the door’s weight. If both springs are broken, then the scale will read the door’s weight. Refer to the outlined initial steps of our Extension Springs replacement tutorial for further clarifications.

If the door has several springs, then the scale should be put under that side of the door which has more broken ones. If the numbers of broken springs are the same on both the sides, then the weight of the door’s middle portion should be found out, and it should be a factor of the number of springs originally on the door divided by the number of broken ones. This procedure will give out the door weight.

The height of the door is also important for the correct choice of the springs. The springs made for 14’ high doors, stretch twice the height than those made for 7’ high doors. Consequently, the un-stretched length of the spring increases with the height of the door.

The length of the spring un-stretched without the ends is to be figured out as well. The ends are known to stretch over time, and thus, the coil needs to be reduced while measuring. The shaft at the center of the spring must be kept straight while the waves are held together. Some springs are worn out so thin that the waves have to be measured for counting the length.

Even though an average spring length exists, usually multiple spring lengths are available for the prevalent door heights.

If, for some reason, the existing spring has to be replaced with a shorter un-stretched length-then the cable has to be adjusted accordingly. 2” of additional length shall be required for every inch missing on your new spring as compared with the existing one. Un-adjustable cables, or short ones can be replaced, or longer spring may do the needful. If you require a spring that has dimension not listed on our parts catalogue, we supply custom-made springs as well. They are 50% more costly than the standard ones, so it is possibly a good idea to replace the cables.

A longer new spring requires the cables to be adjusted which in turn require the S-hooks to be mounted on the new springs.

What Kind of Extension Spring Ends are available?

The three kind of spring ends are open looped, double looped, and clipped ends. They have their pros and cons.

Open looped ends can be easily changed without opening the eye-bolt, or disassembling the pulley. The disadvantage is that the spring relies entirely on the open wires in the end. However, if that is the affected part that is compromised, then placing a clip on the spring end may make it work.

Double looped ones with two coils of spring connecting the eye bolt and the pulley are sturdier than open looped ones. They are harder to replace though.

Clipped ends normally are the best as far as durability is concerned. The spring clips hardly exert pressure on the ends, thus prolonging the spring’s useful life. Generally, Clipped ends normally are used for doors of 200 lb and upwards, and are not easily replaceable.

How many to replace at a time

It is recommended that all the springs should be replaced. Over time, the springs wear out; they fail to provide the required lift, and if not changed cause the door to open unevenly.

Even multiple springs should be changed as changing one would direct all the workload on the new spring and would wear it out faster.

Understanding the Cables and pulleys

Worn out pulleys can be problematic, and should be changed on schedule. It is better to verify the status of the four pulleys as each of them undergoes the same wear and tear while a door opens, and change all of them together even if one is found out to be worn out. This will ultimately be helpful in the future, lowering the shipping cost.

The cables of extension springs too wear out, though they may not be easily detected. Usually, the cable clip is frayed, in a bad state out, and this calls for replacement.

Even if only one cable is faulty, it is advisable to change both of them together for future benefits. The length of the cables determines the cost.

Safety cables are an important accessory for extension spring doors. The cables overlay the entire length of the springs and store the pieces of the springs when broken. This averts mishap and accidents, protecting cars and items of worth from damage when the springs break.

Our extension springs hardware page lists a complete inventory for you to choose from, and order.

Which springs do you need?

Our catalog lists the springs with their corresponding door heights, weight, and the stretch of the springs. You can find the spring that should be of utmost value to you by following the steps described.

Find out the perfect door height for your requirement.

Numbers like 25X42 shall describe the perfect spring stretch. ‘25’ is the un-stretched spring length. ‘42’ would mean that it is for a 7’ high door. Whenever it is time to change your current spring with that of a a unique lenght, the original measure of the stretch should be equal to the un-stretched length of your spring. If there is at least a spring on either side of the door, then the weight points out the weight of the door.