Forklifts are go-to material handling equipment for industries ranging from construction to warehousing because of their versatility. While they are relatively compact machines, they can haul heavy loads thanks to a unique counterbalance design and configuration.
A few key elements impact how much weight a forklift can safely and effectively hold. Explore capacity measurements, rated versus actual load and the stability triangle below.
What Is Forklift Capacity?
Forklift capacity is the total weight of a safe load that a truck can lift and carry. Knowing the weight capacity is critical for operators. Overloading the machine can have unwelcome consequences, such as accidents or damage. Many factors determine a truck's capacity, including engine size, power and fork type.
A machine's capacity is listed on the data plate or in the manual as its rated capacity or maximum load weight.
How Does a Forklift Work?
Forklift mechanics work similarly to a see-saw. Balancing the weight on both ends of the machine keeps it upright and stable. If the weight is uneven, the machine could tip over, causing safety risks.
Lift trucks achieve this balancing act through three key components:
- Fulcrum: The point on the front axle where the lever rests and rotates. It provides a balance between the front load and rear counterweight.
- Counterweight: A metal weight at the back of the truck. It exerts a downward force to counterbalance the front load. The counterweight stops the truck from tipping forward.
- Load-bearing mechanism: The load-bearing mechanism or carriage is the part of the truck that manages the load. Different accessories can connect to the mast, but the standard is a two-pronged fork.
The Stability Triangle
Imagine a triangle extending between the front wheels, with its vertical point at the center of the rear axle. This is the stability triangle and indicates the area of weight distribution. A lift truck's design prevents tipping by distributing weight through:
- Center of gravity: Both the industrial truck and the load have a point of concentrated weight. When a truck lifts a load, these centers of gravity combine. The position of the combined center of gravity within the triangle determines stability.
- Load center: This is the distance from the fork's vertical point to the load's gravity center. The standard load center is 24 inches from the fork faces on a 48-inch by 48-inch pallet. For optimal capacity, balance the haul at the load center.
- Load moment: A moment refers to the load weight multiplied by the load's distance from the front axle. It indicates the ideal weight and the safest distance from the pivot point to avoid tilting.
When you add lift into the equation, the stability triangle transforms into a pyramid. The vertical point now moves toward the top of the truck. Lifting a load shifts the center of gravity out and up. Keeping the center of gravity within the confines of the pyramid prevents tipping.
What Is the Forklift's Maximum Lift Weight?
The lift weight can range from 3,000 lbs to 158,500 lbs. To understand a truck's maximum load capacity, we need to differentiate between the following capacities:
- Rated load: The presumed maximum carry weight based on engineering calculations.
- Actual load: The real-world weight a truck can lift.
These two numbers often differ. For example, say the rated load capacity for an electric 4-wheeler is 12,000 lbs. Factors such as attachments, load distribution or tire type decrease this weight. Attachments like sideshifters add weight and subtract from the load capacity. With the weight of the side shifter, the actual capacity may be around 11,700 lbs.
Five factors that affect a truck's load capacity include:
- Lifting height: The higher the lift, the higher the equipment's center of gravity. The risk of tipping increases if the center of gravity is outside the pyramid.
- Attachments: These add weight to the load and extend the load center forward.
- Load length: The standard load center length is 24 inches. Longer loads cause the load center to increase and the center of gravity to shift forward.
- Load distribution: If the weight distribution is uneven, it causes instability.
- Tire type: The size, tread width and type of the machine's tires can impact a forklift's capacity.
What Are Different Forklift Carrying Capacities?
Now, let's look at the rated capacity of standard trucks from Medley Equipment Company:
- Order picker: 3,300 lbs to 5,500lbs
- 3-Wheel electric: 3,000 lbs to 5,000 lbs
- 4-Wheel electric: 3,000 lbs to 12,000 lbs
- Internal combustion cushion tire: 4,000 lbs to 15,500 lbs
- Internal combustion pneumatic tire: 3,000 lbs to 19,000 lbs
- Rough terrain: 5,000 lbs to 35,000 lbs
Calculating Forklift Capacity
Calculate a truck's capacity by multiplying its length by the rated load center distance. The calculation gets complicated when the load differs from the specified load center. You can use a simple calculation to determine the actual truck capacity. Divide the rated load center by the actual load center, and then multiply that figure by the rated capacity.
An equipment expert can assist you in determining forklift capacity if you need assistance. The Occupational Safety and Health Administration (OSHA) also has a helpful guide on load handling.
Experienced operators can estimate the load capacity based on the truck type. Examples of forklift types and their associated rated load capacity include:
- Pneumatic tire: 36,000 lbs
- Cushion tire: 15,000 lbs
- 3-Wheel electric: 5,000 lbs
- 4-Wheel electric: 12,000 lbs
- Rough terrain: 35,000 lbs
How to Choose the Right Forklift?
Choosing the right capacity for your needs depends on factors including:
- Weight: What is the maximum weight the truck will need to carry?
- Height: How high will the truck lift loads?
- Length: What is the expected length of the longest load?
- Attachments: What accessories or attachments are necessary for your operations?
These answers can help determine the proper load capacity for a new vehicle. If you are unsure, contact a reputable dealer for advice on the best machine.
Trust the Experts at Medley Equipment Company for Your Forklift Needs
Whatever forklift capacity you require, Medley Equipment Company has you covered. We stock top-quality brands, including Hyster, Yale, Combilift, Mariotti, Aisle-Master and more. Customer satisfaction is our top priority, and we've served Missouri, Arkansas, Texas, Oklahoma and New Mexico for over 80 years. You can rely on our industry experts to provide the best solution for your needs.
We have a wide selection of forklifts available, including new, used and specialty options. We also offer equipment rentals to fulfill your short-term project needs.
Discover the Medley Equipment Company difference for yourself. Contact our team of experts for a quote, or view our extensive selection of forklifts online today.
