Garage door torsion spring sizing explained

Updated November 2, 2026. Every manufacturer code and safety rule on this page links to its source below.

The four measurements that define a torsion spring

• Wire size. DASMA defines it as the diameter of the wire in the spring, measured in inches (for example .2070 or .2500). This is what the color code tracks.
• Inside diameter. The diameter of the coil. DASMA lists inner diameter among the crucial design aspects that color does not capture.
• Length. Also outside the color code. DASMA's terminology separates active coils, the working coils of a torsion spring, from dead coils, which the spring plugs make inactive.
• Wind direction. Springs are wound in one direction. DASMA says turns should always be applied in the direction the manufacturer's installation instructions specify, and calls winding a torsion spring backwards a safety issue for the installer.

Two design rules sit behind those numbers. ANSI/DASMA 102-2018 says torsion springs should not be used to balance sectional doors with an index ratio below 6 to 1, meaning the mean coil diameter must be at least six times the wire diameter. And DASMA defines spring balance as the number of turns needed to counterbalance the weight of the door.

Turns and torque: why “a little tighter” is not a fix

DASMA's spring cycle-life sheet is blunt about turns. Too much torque puts excessive force on the other counterbalance parts and is a safety issue for the person applying it. Too little lets the door drift down from its open position over time. The number of turns should always follow the garage door manufacturer's installation instructions. That is why a door that drifts down, feels heavy, or triggers balance-related opener codes (Chamberlain 1-6, 4-2 and 4-4) needs a technician, not a winding bar from the hardware store.

DASMA torsion spring color codes

Manufacturers mark torsion springs with a paint color that identifies the wire diameter. Colors repeat, so the same color covers several wire sizes; DASMA also uses black for sizes that are unspecified or not on the list. DASMA intends this chart for manufacturers and cautions that color codes should be confirmed by physical spring measurements and door weights, especially on older installations.

Extension springs use a different scheme: the color identifies the door weight, in 10-pound steps from 50 to 300 pounds, and DASMA notes two extension springs are required for the listed door weight.

How long springs last, and what shortens it

Spring life is counted in cycles; one cycle is the door moving from closed to fully open and back to closed. The archived 2004 edition of ANSI/DASMA 102 said residential and commercial door systems should be designed to operate at a minimum of 10,000 cycles when properly selected, installed, operated and maintained, and described a residential door as one normally operated fewer than 1,500 cycles a year. The current 2018 edition sends cycle-life testing to ANSI/DASMA 109 rather than repeating that figure. DASMA also notes spring cycle life may not match door cycle life.

DASMA lists these as things that shorten spring life:

• Nicks, notches or rust, which reduce the wire's effective strength and can start fatigue cracks.
• A spring that does not match the door's counterbalance requirement.
• The wrong number of turns, or winding in the wrong direction.
• Extra door weight, for example from paint or added components beyond the manufacturer's specifications.
• Too little or too much stretch on a torsion spring, which makes coils rub.
• Doors left open for long periods in extreme heat, cold, moisture or salty coastal air.
• Skipping the lubrication the door manufacturer's instructions call for.

What you can safely do

• Look, do not touch. With the door closed, DASMA suggests checking from inside for loose cables or any loosening in the spring system, without touching or adjusting the springs or anything they are fastened to.
• Stop using a door with a broken spring. DASMA says not to operate it until the spring is replaced. For how to tell a spring from a cable problem, see spring vs cable and garage door sounds.
• Use the release carefully. Linear's manual says to use the emergency release only with the door closed when possible, because weak or broken springs can make a door close faster.
• Keep up with maintenance the door manufacturer specifies, and keep the door closed when you can in harsh climates, per DASMA.

Questions to ask the technician

• Will you measure the old spring (wire size, inside diameter, length, wind) rather than going by color?
• Is the replacement matched to my door's weight and the door manufacturer's spec?
• What cycle rating is the new spring, and what are the options?
• Will you check the cables, drums and bearings while you are there?
• Will you reset the opener's limits and force and run the 2x4 reversal test before you leave?

For price context, see our repair cost guide, then get written quotes. You can filter the directory to spring replacement specialists.