Garage Door Torsion Springs

The job a wound spring does

A sectional double door weighs somewhere between about 150 and 400 pounds depending on layer count, glazing and material. The opener does not lift that. It only makes up the small amount left over once the springs have balanced the weight, which is why a correctly balanced door can be raised by hand with two fingers and will stay where you leave it at waist height.

The springs do it by storing torque. As the door comes down, the cables turn the drums, the drums turn the shaft, and the springs wind tighter. On the way up that stored energy comes back out as lift. Every other part in the system is reacting to what the springs are doing, which is why an unbalanced door quietly destroys rollers, cables and opener gears over the following months.

Wire size, cycle life, and why they break when they do

A spring is specified by four numbers: wire diameter, inside diameter, length and wind direction. Residential wire usually falls between about .207 and .262 inch, and the specification has to suit the door weight and the drum size together. Fit one that is off spec and the door is unbalanced even on the day it is installed, which is a slower and more expensive failure than a broken spring.

Life is counted in cycles, not years. A standard spring is rated near 10,000 open and close cycles, which is roughly seven years for an average household and considerably less where the garage is the family's front door and the door runs six or eight times a day. High-cycle springs rated 25,000 or more add an estimated $60 to $120 and are worth it on a busy door. We take more spring calls on the first properly cold mornings of the year, and the reason is not mysterious: the spring was already near the end of its cycle life, and a cold morning is simply when it finally lets go.

Why winding bars exist

A wound torsion spring holds enough stored energy to break bones. Unwinding one takes correctly sized winding bars seated properly in the cone, and the usual improvisation with a screwdriver or a length of rebar is how people lose fingers and teeth. The bar can be thrown out of the cone with the full force of the spring behind it. This is the single most dangerous job on a residential garage door, and it is why every reputable source lists it as professional work.

There is one thing worth doing yourself, and it is the opposite of what most people try. If a spring has snapped, pull the emergency release cord, leave the door down, and use another way out of the garage. Forcing it up with the opener turns a spring job into a bent track, a jumped cable and a much larger invoice the same afternoon.

Replacing one spring or both

On a two-spring door, both springs have done the same number of cycles. When one breaks, the other is at the same point in its life, and replacing only the broken one usually means a second call within a year or two, plus a second labor charge. A matched pair fitted at an estimated $265 to $450 is generally the cheaper outcome over five years, and it keeps the door balanced evenly across the shaft.

Ask the technician to check the balance after fitting rather than just testing that the opener works. With the opener disconnected, the door should stay roughly where it is left at knee, waist and shoulder height. A door that creeps down or races up is telling you the spring is not right for the weight, and that is far easier to correct on the day than six months later.

This part rides on the truck for calls across Canyon Creek and Richardson Heights and the rest of Richardson, so the repair normally finishes on the visit it was booked for.