Look above your garage door and you’ll see either one thick coil or two thinner coils sitting side by side on the shaft. Both setups are normal, and both do the same job — but the differences matter when it comes to how your door behaves, how long the springs last, and what a replacement involves. Here’s what homeowners should know about single versus double torsion spring systems.
What Each Setup Looks Like
A single torsion spring system uses one large spring, usually mounted slightly off-center on the shaft. It’s common on lighter single-car garage doors. A double torsion spring system uses two springs — one right-hand wound, one left-hand wound — mounted on either side of the center bearing bracket. You’ll find doubles on most double-car doors and on heavier doors of any size, including insulated and wooden doors.
Neither setup is inherently “better.” The choice is about matching the spring system to the door’s weight. A single spring sized for a light door works perfectly well; the problems start when a door is heavy enough to need two springs but only has one.
Balance and Smoothness
The biggest practical difference is balance. Two springs share the load, so each one works less hard than a single spring carrying the full weight alone. That shared load means smoother, more even lifting — and, importantly, a safety margin. If one spring in a double setup breaks, the remaining spring still provides some counterbalance, which can keep the door from becoming completely unmanageable (though you still shouldn’t operate it).
With a single spring, there’s no backup. When it breaks, the door instantly becomes full dead weight. That’s why a single-spring door with a broken spring often can’t be opened at all, while a double-spring door might still budge — barely — on one spring.
Lifespan: Doubles Last Longer Per Spring
Because each spring in a double setup carries roughly half the load, the individual springs typically last longer than a single spring carrying everything. That doesn’t mean a double system never needs service — both springs age together, and when one fails, the other is usually close behind. Which brings us to an important rule of thumb.
Always Replace Both Springs Together
If you have a double spring setup and one spring breaks, replace both. This is one of the most consistent recommendations in the industry, and for good reason: both springs have endured the same number of cycles, the same temperature swings, and the same wear. The surviving spring is living on borrowed time, and you’ll pay for a second service call when it fails weeks or months later. Replacing both at once costs only modestly more in parts and saves you the hassle and expense of doing the job twice.
- One spring broken in a double setup? Replace both — the other is nearly worn out too.
- Mixing a new spring with an old one creates uneven tension and poor balance.
- Both springs should match in size, cycle rating, and manufacturer.
| Single spring | Double springs | |
|---|---|---|
| Typical doors | Light single-car doors | Double doors, heavy/insulated doors |
| Load per spring | Full door weight | Roughly half each |
| If one breaks | Door becomes dead weight | Some counterbalance remains — still don’t use it |
| Replacement rule | Replace the one spring | Always replace both together |
| Balance | Adequate for light doors | Smoother, more even lifting |
Can You Upgrade From Single to Double?
Sometimes. If your door is heavy enough that a single spring is working at its limit — signs include short spring life, a straining opener, or a door that never quite balances — converting to a double spring setup can be a smart long-term move. It requires a longer shaft, a center bearing bracket, and two correctly sized springs, so it’s a bigger job than a straight replacement. A technician can tell you whether your door is a good candidate.
Wondering whether your door has the right spring setup — or dealing with a broken spring right now? Call Coppell Garage Door Experts at (945) 404-0050 for an honest inspection and upfront pricing.