Why high-cycle springs make sense on busy warehouse doors

The short version

A high-cycle spring is a torsion spring built from heavier wire and a longer coil, so it carries the same door with less stress on each turn and lasts through far more open and close cycles. On warehouse and distribution centre doors that run all shift, standard springs are often worn out long before anyone expects. High-cycle springs cost more up front but break less often, so the door is out of service less.

Standard springs are rated for far fewer cycles than a busy warehouse door runs
High-cycle springs use heavier wire and longer coils to spread the stress
They cost more up front and last much longer on doors that open all shift
Replace springs in pairs and reset the balance so the operator isn't straining
A broken spring with the door half open means the door comes out of use until it's repaired

How a torsion spring wears out

The springs on a sectional overhead door do most of the lifting. Each time the door opens, the springs unwind and hand their stored force to the cables and drums. Each time it closes, they wind back up. Every one of those turns flexes the steel a little, and after enough turns the wire cracks and the spring snaps.

Springs are sold by how many cycles they are expected to last. A standard spring is built for a door that opens a few times a day. A busy warehouse door can run that many cycles in an hour. The spring isn't faulty when it breaks early. It simply reached its limit sooner because the door works harder.

What makes a spring high-cycle

A high-cycle spring does the same job with less strain on the steel. It is usually wound from thicker wire with a larger inside diameter and more coils, so each turn bends the wire less. The door feels the same to lift, but the spring lasts much longer before it fatigues.

The trade-offs are simple:

Up-front cost. Heavier springs cost more than standard ones.
Space on the shaft. Longer springs need room above the door, so we check the headroom and shaft length first.
Matching the door. The spring has to be sized to the door's weight and height, or the balance will be off.

Signs your doors need them

You likely need high-cycle springs if any of this sounds familiar:

Springs on the same door keep breaking, sometimes on a schedule you could set a calendar by
The door is used for shipping and receiving through every shift
A broken spring has left a door stuck half open during loading
The operator strains or slows down as the springs get tired
Doors drift down or won't stay open because the balance has gone

When several doors at a building break springs often, it usually isn't bad luck. It's a sign the springs were never sized for the work those doors do.

Why we replace springs in pairs

Most large doors run two springs on one shaft. If one breaks, the other has lived through the same cycles and is close behind. Replacing only the broken one means a second visit soon after. We change both, match them to the door, reset the tension, and test the balance so the door stays put at mid-height. A door in balance is also easier on the operator, since the motor isn't lifting weight the springs should carry.

While the door is apart, we check the cables, drums, bearings and rollers. On a door that cycles all shift, these wear at the same pace as the springs.

Cold mornings in Surrey

Inland parts of Surrey, like Cloverdale and Clayton, see slightly colder winter nights than the rest of the city. Cold makes tired spring steel more likely to give way, so the first cold mornings of the season often bring a run of breaks. If your doors are already on worn springs heading into winter, this is a good time to have them looked at.

What to do when a spring breaks

A broken spring usually means the door won't lift, or it comes down hard. Don't keep running it with the operator, and keep people and forklifts out from under it. Leave it secured and call it in.

To help us bring the right springs on the first visit, send:

The door's width and height and rough age
The panel type, such as insulated steel
The operator brand, if there is one
Photos of the spring and cable area above the door

Most spring, cable and roller repairs take a few hours. We book them early, late or between shifts so only one door is out at a time, and you get a quote before any work starts.