Garage Door Systems: A Comprehensive Guide into What Makes Them Work

Chances are you’re familiar with how to open a garage door. You either have a button or switch that you press on the inside of your garage, close to the interior door, you have a numbered access code that you can punch in, or you have a garage door remote hanging from the visor of your car. It’s easy. You press a button and it opens. We tend to skip over thinking about what goes in to the process that makes a garage door function because we no longer have to get out of our cars and manually lift them off the ground.

We take advantage of the fact that our garage door is motorized and works as a system made up of working parts that we don’t need to consider. We don’t think about how often we open and close our garage doors – which happens to be between 1,000 and 2,000 times per year depending on family size, entry point, and accessibility. That’s a lot of wear and tear. Nevertheless, when something goes wrong it usually isn’t because the entire system has broken down all at once. Chances are that only one piece of the puzzle has stopped working and knowing what that is can save you time, money, and tons of stress.

To boost your knowledge on all things garage door systems, we figured we’d give you a comprehensive guide to understanding how a garage door system works. There are a few different types of operators, which we’ll get into, but most of them have the same basic components that contribute to opening and closing your garage door. Let’s take a look at their similarities first.

The Door

Sounds basic, but it is part of the garage door system. Your door is your primary line of defense and is important in the integrity of how your system operates. While there are a ton of different types of garage doors to choose from, the differences don’t make too much of an impact on how the system works. You will likely have sectional door where there are steel panels separating different areas that will bend and curve during opening and closing. This means that if you incur damage you won’t need to replace an entire door. If you need to replace your garage door, talk to a trusted professional about your options and what is right for you.

The Frame

The frame encompasses all of the parts of your garage door system that don’t move. They’re used to guide your door and the moving parts along a track in order to keep everything safe and in place. When all else is in motion, the frame remains stationary. While these parts don’t contribute to the actual movements that open and close a garage door, the system would fail without them.

Vertical and Horizontal Door Track

This is the part of your garage door system that will guide your door up, down, and across your garage ceiling as the system operates. Without tracks, the system simply wouldn’t exist. It’s the underlying skeleton that’s needed in order for movement.

Trolley Track

Similar to vertical and horizontal door tracks, the trolley track is the track that guides the pulley, chain/cable, and belt up and towards your operating system. It is the middle rack that hangs from your ceiling between the horizontal tracks.


In order to attach your tracks to the infrastructure of your home, you need flag and jamb brackets. Flag brackets are installed at the 90-degree angle where vertical and horizontal door tracks meet and jamb brackets are secured at the bottom of the garage door to ensure that it is 100% closed. These brackets need to be extremely strong in order to hold the weight of the tracks and door in place.

Hanger Kit

A hanger kit connects the horizontal door track to the ceiling along with the main operator that you use. These are completely adjustable, so you can be sure that the parts of your frame fit your garage and are easily repairable.

Bottom Rail

This is a specific horizontal track that is at the lowest part of your system. Oftentimes you won’t see the difference between a bottom rail and your garage door, but both are attached to each other to ensure your door is fully closed and avoids damages.

Moving Parts

To better understand your garage door system as a whole, you need to understand all of the moving parts. This includes all of the small hinges, screws, nuts, and bolts described below.


These are, as they sound, what rolls your garage door up and over on the vertical and horizontal tracks. Without rollers, your garage door would scrape open and close and make for a less than ideal experience – both in noise and safety.


Hinges are used throughout the garage door and facilitate folding at the crease when your door moves from a vertical position to a horizontal one. There are a number of hinges connected throughout the inside of your garage door and work in unison when lowering and closing as well as when holding your door in a static position.

Pulley and Cable

A pulley and cable are the essence of the moving parts of a garage door system. They are what work together to lift a door and move it along the belt to the operating system. Since garage doors are usually heavy, a pulley allows the cable to lift more weight than it would be able to alone and releases that weight in a smooth, gentle manner.

Curved Door Arm

This piece attaches your garage door to the trolley system and pulley and cable. It’s what physically connects and pulls the door up, down, and along your belt system.

Torsion Spring

The torsion spring is located across the top of your garage door and helps to lift your door off the ground and along the tracks. The twisting motion of the spring forces your door into motion. If your garage door isn’t opening when using your remote, or if it opens just a little and closes again, it’s likely that your torsion spring is broken. This is the most common type of garage door system failure as springs rust and wear out. If you aren’t sure how to safely replace this on your own, it’s best to call in a professional.

Cable Drums

These are another common culprit of non-functioning garage doors. They give your cables a place to rest and are used in the gear-shifting manner to slide your door along the trolley.

Chain, Belt, or Screws

Depending on the type of operating system you have (see below) you will either have a chain, belt, or screw. These are what move through all of the above moving parts in order to actually pull your garage door open and closed. Depending on your needs, each option offers its own advantages and disadvantages.

Emergency Release Cord

All garage door opener systems come standard with an emergency release cord for safety purposes. When you pull on this cord, your garage door is completely detached from the trolley system and belt – enabling you to manually open or close your garage door. This is your safety in case you have any maintenance issues or you lose power.

Finally, you have what is called a motor drive or operator. This is the electronic mechanism of your system that will work to connect all of the moving parts and either open or close your garage door. There are four main types of drives: the chain drive, belt drive, screw drive, or direct drive.

Chain Drive

A chain drive operates on a system with a metal chain that works in conjunction with the trolley track to open and close your door. While they’re inexpensive, they can be fairly loud.

Belt Drive

A belt drive uses a rubber belt in conjunction with the trolley track instead of metal. These are a bit less complicated than other types of drives and usually don’t require as much maintenance throughout the year.

Screw Drive

This type of operating system uses a rotating threaded steel rod to move your trolley and open and close your garage door. There aren’t very many moving parts to this type of operator, which is great for low maintenance homeowners.

Direct Drive

When you utilize a direct drive, your operating system actually moves along the belt with the trolley. This means it’s the drive with the fewest parts – there are no belts or chains used – and can often go years without needing any maintenance.

While you may understand all of the parts that make up a garage door system, if you can’t immediately pinpoint the problem, it’s always best to call a professional. In fact, hiring a trusted garage door service will make a huge difference in both the safety and functionality of the work done. Check out information on the Better Business Bureau for location specific companies and make sure that your contractor has all of the licenses, certifications, and experience you want in a professional service. If you have any questions please feel free to call our office.