How a garage door stays balanced, and a safe balance check

A balanced garage door is held up by its springs, not by the opener. This guide explains what balance means and the signs of imbalance you can spot by eye. The hands-on balance test is technician work, because it involves a spring-loaded door.

Your springs counterbalance the weight of the door. When the system is balanced, the springs carry almost all of the door's weight. That is why a well-balanced door can be lifted by hand, and why the opener only has to guide it. Clopay notes that an unbalanced door puts excessive strain on the springs, which leads to premature wear.

Balance depends on the spring matching the door. DASMA says that not knowing whether a spring meets a door's counterbalance requirement can shorten spring life and create a manual-operation safety issue. Added paint, windows or other components can push the door heavier than the springs were sized for.

You can notice most of these during ordinary use without testing anything:

• The door feels heavy, or the opener sounds strained or runs slower than it used to.
• The door moves unevenly or jerks.
• The door closes too quickly or slams. See garage door closes too fast.
• One side sits lower than the other. See door hangs crooked.
• The door will not stay open partway.

These signs overlap with a failed spring, a cable problem, worn rollers or a bent track. We do not diagnose from symptoms alone. A technician inspects the door and confirms the cause.

Do these from the floor with the door at rest. Nothing here requires you to lift or release the door.

1. Look at the closed door from across the garage. The bottom edge should sit level on the floor with no gap along one side.
2. Look at the springs for rust, a gap in a coil, or a stretched or deformed spring.
3. Look at the cables at the bottom corners for fraying, slack, or a cable off its drum or pulley.
4. Notice whether the opener works hard or strains in normal use, and whether the door slows or jerks.
5. Write down what you notice, including any change since the door was last serviced, and take photos.

If any item looks wrong, stop there and bring in a technician.

You will see a balance test described in many online guides. They typically say to disconnect the opener, lift the door halfway by hand, and let go. A balanced door stays put. One that drops or rises is out of balance. Clopay, This Old House and others describe the test this way.

We do not recommend that homeowners do this test. It means releasing the door from the opener and holding a spring-loaded door that may be heavier than it feels. If a spring has weakened or a cable is worn, the door can drop on you or on a vehicle. The same sources say that a door that fails the test needs professional adjustment, and spring tension is not something to change by hand.

Our technicians check balance as part of the visit. DASMA notes that a trained technician can measure door weight with a scale after the counterbalance system is disabled, and that the counterbalance assembly should be maintained according to the door manufacturer's written instructions.

• The door feels heavy, slams, or will not stay open partway.
• One side hangs lower than the other, or the door looks crooked.
• You see a gap, rust or stretching in a spring, or fraying in a cable.
• The door has been painted, insulated or fitted with windows since the springs were installed.
• The opener strains, hums or struggles. See opener hums but the door does not move.

We inspect the door, confirm the cause, and adjust or replace springs as needed. See spring replacement, garage door repair, and maintenance and tune-ups. If you want to know whether a spring may have failed, see signs a spring is broken.

• Garage Door Spring Replacement
• Garage Door Repair
• Garage Door Maintenance and Tune-Ups

• DASMA: Garage door safety
• DASMA Technical Data Sheet 190: Factors affecting spring cycle life
• Clopay: Understanding garage door springs
• This Old House: Replacing garage door springs
• A1 Garage Door Service: Understanding garage door springs