Categories
Garage doors

What Size Spring for Garage Door?

This post tells you how to choose garage door torsion springs based on door weight.

Garage door torsion springs are sized on wire diameter (d), inside diameter (D) and length of the coil (L). Eg. .250″ – 2″ – 32″ means .25″ wire, 2″ inner diameter and 32″ coil length.

Knowing which spring sizes work on your door is tricky. Many sizes actually fit and provide different lifetimes. There are color coding systems but they are still manufacturer-dependent and not completely adopted.

The tables below help you out. I have calculated the values for standard 7 ft. or 8 ft. door heights and a 4″ drum. If you have a non-standard combination, please see my Garage Door Spring Calculator.

Spring Size Chart – 7ft. height

This table lists fitting torsion springs by door weight for a 7 ft. tall garage door. The table lists weights both for a single and a dual spring configuration.

SPRING
BY
DOOR
WEIGHT

Door
Weight
(Single
spring)
[lb]
Door
Weight
(Dual
springs)
[lb]
(7ft door,
4in drum,
7½ t. preload)


TORSION
SPRING
CODE
[d-D-L]
Spring
life
[cycles]
85 lb.170 lb..207”-2”-23”21k
90 lb.180 lb.
180 lb.
.207”-2”-22”
.207”-1-3/4”-25”
17k
18k
100 lb.195 lb.
195 lb.
205 lb.
205 lb.
.207”-2”-20”
.218”-2”-26”
.218”-2”-25”
.225”-2”-29”
13k
23k
19k
29k
105 lb.210 lb..218”-2”-24”17k
110 lb.220 lb..218”-2”-23”
.225”-2”-27”
14k
21k
115 lb.230 lb..218”-2”-22”
.225”-1-3/4”-29”
12k
17k
120 lb.235 lb.
240 lb.
.225”-2”-25”
.218”-2”-21”
15k
10k
125 lb.245 lb.
245 lb.
250 lb.
.225”-2”-24”
.207”-1-3/4”-18”
.234”-2”-29”
14k
short
20k
130 lb.255 lb.
260 lb.
260 lb.
.234”-2”-28”
.225”-2”-23”
.243”-2”-33”
18k
12k
26k
135 lb.265 lb.
270 lb.
270 lb.
.225”-1-3/4”-25”
.225”-2”-22”
.243”-2”-32”
10k
10k
23k
140 lb.285 lb..250”-2”-35”27k
145 lb.285 lb..218”-1-3/4”-20”short
150 lb.300 lb.
305 lb.
.243”-2”-29”
.243”-1-3/4”-32”
16k
15k
155 lb.310 lb..250”-2”-32”18k
160 lb.320 lb..250”-2”-31”16k
165 lb.330 lb..250”-2”-30”15k
170 lb.340 lb..250”-2”-29”13k
175 lb.350 lb.
355 lb.
.250”-1-3/4”-32”
.250”-2”-28”
12k
12k

Use example: A typical 9×7 ft. door weighs around 100 lb. and has four spring options in the chart: .207″-2″-20″, .218″-2″-26″, .218″-2″-25″ and .225″-2″-29″. The first gives the shortest and the last the longest service life.

A wider 16×7 ft. door could weigh ~180 lb. and optimally takes a dual-spring setup to balance. The chart gives two size options: .207″-2″-22″ and .207″-1-3/4″-25″, both with a similar life. (A single-spring setup with .250″-1-3/4″-32″ or .250″-2″-28″ may just work, too.)

Spring Size Chart – 8ft. height

This table lists fitting torsion springs by door weight for a 8 ft. tall garage door. The table lists weights both for a single and a dual spring configuration.

SPRING
BY
DOOR
WEIGHT

Door
Weight
(Single
spring)
[lb]

Door
Weight
(Dual
springs)
[lb]
(8ft door,
4in drum,
8½ t. preload)


TORSION
SPRING
SIZE
[d-D-L]
Spring
life
[cycles]
95 lb.195 lb..207”-2”-23”13k
100 lb.205 lb.
200 lb.
.207”-2”-22”
.207”-1-3/4”-25”
11k
12k
110 lb.225 lb.
220 lb.
.207”-2”-20”
.218”-2”-26”
7k
14k
115 lb.230 lb.
230 lb.
.218”-2”-25”
.225”-2”-29”
13k
17k
120 lb.240 lb..218”-2”-24”11k
125 lb.250 lb..218”-2”-23”
.225”-2”-27”
9k
13k
130 lb.260 lb..218”-2”-22”
.225”-1-3/4”-29”
7k
11k
135 lb.270 lb.
275 lb.
.225”-2”-25”
.218”-2”-21”
10k
short
140 lb.280 lb..225”-2”-24”
.207”-1-3/4”-18”
.234”-2”-29”
8k
none
13k
145 lb.290 lb..234”-2”-28”
.225”-2”-23”
12k
6k
150 lb.295 lb.
305 lb.
.243”-2”-33”
.225”-1-3/4”-25”
16k
short
155 lb.305 lb..225”-2”-22”
.243”-2”-32”
short
14k
160 lb.320 lb.
325 lb.
.250”-2”-35”
.218”-1-3/4”-20”
16k
none
170 lb.340 lb.
345 lb.
.243”-2”-29”
.243”-1-3/4”-32”
10k
9k
175 lb.350 lb..250”-2”-32”12k
180 lb.365 lb..250”-2”-31”11k
190 lb.375 lb..250”-2”-30”9k
195 lb.390 lb..250”-2”-29”7k
200 lb.395 lb.
400 lb.
.250”-1-3/4”-32”
.250”-2”-28”
6k
6k

How accurate is the weight rating?

The garage door weight should be within +-5% of the value in the tables. The pretension gives you some room for adjustment in the balance, but is only for fine-tuning.

How is spring life calculated?

The indicated spring lives in cycles are calculated using fatigue curves for the steel used in door springs. I inferred the fatigue curves (also S–N curves) from manufacturers’ spring ratings. The actual spring life will vary +- 30% around the nominal value. Please also see my post on spring wear.

Can garage door springs be too strong?

Garage door springs can be too strong (or too weak). If the springs are not matched to the door weight, they will not work: they cannot be tensioned to so that they would balance the door evenly through its travel.

Spring stiffness is what is critical, not ultimate strength. Spring stiffness, or spring rate, determines how much torque and lift the spring gives per revolution.

Can I use a heavier spring on my garage door?

You can use a heavier spring on a garage door if the spring stiffness is the same. Such springs would have the same weight rating in the table above. You can also check the IPPT (Inch-Pounds Per Revolution) specification of the springs match.

Different weight springs can (perhaps surprisingly) have the same stiffness. If a spring is both longer and made of thicker wire, it can have the same stiffness as the original.

Should I use one or two torsion springs in my garage door?

Lighter doors take one spring, heavier ones take two. If your door is 7ft. tall and under 175 lb, it can be balanced with one standard spring; if it’s above 175 lb you’ll need two. For the taller 8 ft. doors, the cutoff is at around 200 lb.

If your door weighs around 170….175 lb or 195….200 lb you can choose to use either one or two springs. Dual springs will cost you more but give a longer service life. They also reduce axial loading on the bearings.

NB. Adding a second spring to a working single-spring door never works. When going from one to two springs, you must change the type – refer to the tables above.

The options are summarized in the table below:

NO. SPRINGS
vs.
DOOR WEIGHT
Weight,
7 ft. door
Weight,
8 ft. door
Single spring175 lb.
or lower
200 lb.
or lower
Two springs170 lb.
or higher
195 lb.
or higher
One/two springs170…175 lb.195…200 lb.