Understanding the Forklift Stability Triangle (Forklift Operators)

Understanding the Forklift Stability Triangle (Forklift Operators)

Fleet Maintenance | Forklift Repair | 03/29/2024
Written by Stacy Conner

Sometimes, it can be helpful to understand challenging concepts with a simple model.

For example, we can use a helpful concept — the forklift stability triangle — to describe forklift stability.

Forklift operators, drivers, and fleet managers: you may have heard the term “forklift stability triangle” thrown around before.

And if you’re confused — or curious — about what it is, you’ve come to the right place. We can help.

For more than 20 years, our master diesel repair technicians have been providing fleet managers, operators, and drivers with quality fleet equipment repairs, preventive maintenance, and forklift education.

Whether you’re wondering what the term means — or are looking to understand how to ensure your forklift is more stable — we got you covered. We’ll unpack the concept of the forklift stability triangle so you can create a more stable and dependable forklift operation.

Let’s dive in!

The “forklift stability triangle” concept explained

An industrial forklift carrying and stabilizing a shipyard crate

The forklift stability triangle is a concept that can help forklift operators better understand how to maintain stability in a forklift. It’s no coincidence that a triangle is used to explain forklift stability.

Let’s take a look at how the symbol helps describe forklift stability. The invisible triangle is formed by the pivot point on the rear axle and the two front wheels of the front axle.

You might have heard the center of gravity of a forklift described as being positioned “within the forklift stability triangle.” This phrase is a fancy way of saying that a forklift won’t tip over, so long as the center of gravity is well-aligned on the forklift.

A forklift carrying more than its carrying capacity — or a forklift load whose center of gravity shifts too far forward — can cause a forklift to tip over. A forklift whose load is no longer within the “forklift stability triangle” is subject to accidents.

Fortunately, there’s a way to keep your forklift stable. By knowing which factors impact forklift stability, you can take control of your forklift so it carries you through all your lifting needs.

A forklift picking up a load from the top of a semi-truck flat bed trailer

Before describing the factors that impact forklift stability, let’s take a quick look at a few key terms related to the stability triangle. Knowing these terms will help you better understand how to operate your forklift, as well as how to train your team to better operate your forklifts.

Being familiar with these Occupational Safety and Health Administration (OSHA) safety terms will give you a shared vocabulary when it comes to your next team safety training. With this new knowledge, let’s look at the factors that impact a loaded forklift’s center of gravity.

3 Factors that impact forklift stability

A blue and white forklift inside of a warehouse

Three main factors impact a forklift’s overall stability, including:
1. The type of forklift used
2. The load size carried by the forklift
3. The type of terrain you’re driving on with your forklift

Each of these factors can affect the center of gravity, weight distribution, and stabilization of your forklift. We’ll explain why in the next sections.

1. The type of forklift you’re operating

The type of forklift you drive can affect the stability of your forklift. Since each forklift has its own stability profile, it’s important to look at the specifications of your forklift to see which forklift is best for the job.

For example, a small hand-held pallet jack may not be a great option for heavy-duty warehouse lifting. Likewise, a lift truck with cushion tires might not be great for a heavy-duty outdoor lifting task.

The type of forklift you drive can affect the load’s center of gravity. Finding the right forklift for the job can help reduce the risk of goods and equipment being damaged or crushed.

2. The forklift load size

It goes without saying that the size and weight of a load can affect a forklift’s stability. The distribution of the load is just as important.

Check your forklift operator’s manual, as it will describe what size and distribution is acceptable for your forklift. Keeping your load balance as close as possible to the acceptable size and distribution will ensure your forklift is safe for operation (and doesn’t become a safety hazard).

3. The terrain you’re driving on with your forklift

Every forklift has a different weight-carrying capacity. Some forklifts aren’t meant to operate on certain terrain.

Lift truck operators: the terrain you’re operating on can affect the stability of your forklift. When a load is raised, the chances of an accident occurring increase.

In general, holes, bumps in the road, steep inclines or declines, and other hazards can cause the front wheels and the center of the forklift to elevate. We recommend doing your best to avoid operating a loaded forklift on oily, slippery, wet, or uneven surfaces. 

3 Tips to help improve forklift stability

A person stabilizing a stack of wood pallets on forklift forks

While it may look like a forklift is easy to tip, there’s still quite a bit within your power to help keep the center of gravity of the load as close to the middle of the stability triangle as possible. The following three tips should help ensure that the weight of the load stays centered on the forks of your forklift:

1. Keep your load low to the ground
2. Operate your forklift slowly and evenly at all times (no sudden braking or accelerating)
3. Always carry a safe load capacity (don’t exceed your forklift’s maximum load capacity)

1. Keep the forklift’s load low to the ground

We recommend keeping your forklift no more than 4 to 6 inches off the ground and sticking to OSHA’s recommendations. For example, OSHA suggests tilting the mast back and keeping the heaviest part of a load in the carriage section.

Do your best to make sure the center of gravity remains as close to the center of the stability triangle as possible. Doing so will help you better secure and carry heavy loads.

2. Keep your forklift steady while accelerating or braking

“No sudden stops,” our parents used to say. While it may have been a while since the first time we first started driving, our parents were right.

To ensure the center of your load doesn’t move outside the stability triangle, operate your forklift at a safe and comfortable speed. Quick accelerations and sudden stops can shift the center of gravity of the load outside the three points of contact within the stability triangle.

And you know what that means: accidents and tipping.

To avoid tipping and accidents, operate your forklift at the speeds posted in your warehouse and in line with your forklift operator’s manual.

3. Stay within (or below) your forklift’s maximum load capacity

While it can be tempting to load up a forklift beyond its max capacity, we strongly advise against carrying more than your forklift can handle. When a load is too heavy, it can cause a vehicle to tip.

Worse yet, if the vehicle tips, the driver could lose control of the steering, and goods (or people) could be crushed under the weight of the load. To avoid accidents, it’s important not to exceed the load capacity listed on the data plate of your forklift.

If in doubt, you can always reach out to an Equipment Experts master diesel technician or your forklift operator’s manual for guidance on operating your forklift within its carrying capacity.

It pays to understand the forklift stability triangle

An aerial view of the Equipment Experts, Inc. team in front of their fleet of trucks

The forklift stability triangle is a concept that helps forklift operators better keep load weight distributed across the center of the forks of a forklift. The three factors that influence the distribution of weight across a forklift include the forklift model, the terrain operated on, and load size of a forklift.

You can increase the stability of your forklift by lifting your load no more than 6 inches from the ground, avoiding sudden accelerations or stops, and carrying less than its total carrying capacity.

Between maintenance schedules, adhering to OSHA trainings, and operating your fleet, keeping in mind the forklift stability triangle can be tough. The diesel repair technicians at Equipment Experts, Inc. can do the heavy lifting for you.

Our mobile and in-shop forklift repair technicians have helped ease the burden of forklift operations for countless fleet teams. For more expert advice on forklifts — or just to chat about fleet maintenance — don’t hesitate to contact our fleet team.

We’d be more than happy to provide you with expert advice for all your forklift needs. Until then, safe lifting to you all!

Frequently asked questions (FAQ) about forklift stability

A gentleman in the seat of a forklift talking to a person outside the forklift

Why the term “forklift stability triangle?”

Simply put, this term allows us to describe forklift stability with greater ease. For example, this term is a much shorter way of describing longitudinal, lateral, and dynamic stability and how stability depends on the three-point suspension system of a forklift. It’s a mouthful, right?

We simply say that the two front wheels and center of the steer axle form three points — a triangle!

Using a triangle is an easier way to describe the concept of balancing a load.

Where is the load center on a forklift?

A load’s center is located within the perimeter of the triangle. The center is formed between the forklift’s two front wheels and the center of the steer axle.

How can I improve my forklift’s stability?

The best ways to keep your forklift in tip-top shape is to do the following:

But, in case you need forklift maintenance, you can always bring your forklift in for repairs. With forklift sales set to increase by nearly 50% over the next six years, it’s never been a better time to have your forklift repaired.

To keep your forklift in tip-top shape, don’t hesitate to reach out to a diesel repair mechanic near you.

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