What Are the Legal Axle Weight Limits for Commercial Trucks?

Over-dimensional freight, especially overweight freight, causes extra difficulties during transit — the mass of the freight makes it harder to stop quickly, and excess weight can damage the surface of the road and the ground underneath. 

Experienced drivers compensate for the extra stopping distance by allowing a greater following distance and traveling at a slow, steady speed. 

Damage to the ground can be mitigated by adding more axles to the vehicle. Just as a building’s foundation distributes the weight evenly over a larger area, multiple truck axles spread the weight of the loaded vehicle to prevent damage to the road. 

Each state has different regulations for the maximum gross vehicle weight (total weight of the loaded truck and trailer) allowed on their roads. These weight regulations are based on the state’s infrastructure and what the roads can safely support. 

In addition to a total weight limit for a loaded truck, most states have weight limits for single axle, double axle and tri-axle trucks. These limits help preserve the quality of the road and provide an important public safety function. 

Since 1955, Anderson Trucking Service (ATS) has been hauling freight nationwide. We have extensive experience with heavy-haul shipping and the rules that govern it in every state. 

Because we place such a high priority on safety, we want to help everyone on the road understand the state-by-state rules that govern overweight vehicles. Read this article for an explanation of why weight limits matter, and for a breakdown of each state’s guidelines. 

What Is the Federal Maximum Gross Vehicle Weight for a Truck? 

Safety guidelines set by the federal government establish legal weight limits for a loaded semi-truck and trailer. Factors that determine this weight limit include:

• The federal bridge weight formula (a maximum legal weight-to-length ratio)
• Maximum legal weights allowed per group of axles
• An overall gross weight of 80,000 pounds on the interstate system

In addition to the federal limits, each state has individual weight limit guidelines based on the number of axles and axle distance. These state limits apply to state highways that are not part of the interstate system. 

Federal and state weight limits include the weight of the hauling equipment and the freight, whether it’s one large object or a collection of individual pieces like steel I-beams that can be arranged for even weight distribution.  

This limit applies to the overall weight of the vehicle. Over-dimensional freight is also subject to limits on each axle.

The 80,000-pound limit includes the curb weight of the empty truck and trailer, which will vary depending on the type of vehicle. 

Dry van trailers, for instance, weigh more than flatbed and step-deck trailers due to the enclosed trailer that protects van freight from the elements during transit. This added weight means that dry van trailers have a lower load weight capacity than other trailer types.

The tractor that pulls each load must also be accounted for in the total gross weight. These usually amount to about 32,000 pounds. 

It is important to note that the construction of various trailer types also contributes to their overall weight, resulting in differences in load capacity. To provide a general reference, here are the typical freight-weight thresholds for the three most common tandem-axle trailer types:

• 53-foot refrigerated trailers: 43,000 to 45,000 pounds
• 53-foot flatbed trailers: 45,000 to 48,000 pounds
• 53-foot dry van trailers: 43,000 to 46,000 pounds

This freight capacity weight must be evenly distributed among the truck’s axles, including the steer axle and the two drive axles.

What Are the Legal Weight Limits By Axle? 

A load is considered over legal weight if it exceeds the weight limit on any axle group, even if the gross weight is under 80,000 pounds. Any freight that exceeds an axle weight limit or the total gross limit requires a permit for every roadway along the route.

This is the point where legal axle weight limits and weight distribution are important. There are specific definitions for axle groups including single, tandem, and tridem-axle. Let's delve into these weight limits and regulations further.

What Is the Legal Weight Limit For Single-Axle Trailers?

Single-axle transportation equipment is limited to a maximum legal weight of 20,000 pounds per axle. This limit applies to any single trailer, booster or stinger axle.

Larger freight that exceeds the limits for a single axle requires a larger trailer for transit.

What Are the Weight Limits for Steer Axles?

Regardless of the number of axles on the vehicle, the front steer axles of a semi-truck typically weigh 11,000-15,000 pounds (roughly 500-600 pounds per inch of tire). This weight varies depending on the tires and the unique semi-tractor size, make, model and rating.

This is true of any size vehicle, regardless of the number of other axles.

What Is the Legal Weight Limit For Tandem-Axle Trailers?

Tandem-axle trailers, which have each axle spaced between 40 inches and 96 inches apart, are legally allowed to carry up to 34,000 pounds of weight on two axles. The weight must be balanced and distributed evenly to not exceed the weight on any one axle.

When combined with the two drive axles on the semi-tractor, standard tandem-axle trailers like step-decks and flatbeds can each legally accommodate up to 48,000 pounds without requiring a permit.

However, it's important to note that each state tandem weight regulations for tandem-axle weights may be lower than the federal limit. This is why it's crucial to consult with an experienced transportation provider before moving overweight freight. 

As a general rule of thumb, you can carry permitted loads up to of 34,000-44,000 pounds on a tandem axle in the majority of states.

How Much Gross Weight Can Be Permitted On a Tandem-Axle Trailer?

As a general rule of thumb, you can permit 40,000-44,000 pounds on a tandem axle in the majority of states, bringing the freight weight limit to roughly 45,000-58,000 pounds. Remember, only non-divisible loads can be permitted.

The weight limit that can be permitted on a tandem-axle trailer will depend on the states you will be traveling through and the specific limits of the hauling equipment. Many tandem-axle trailers are not designed to bear excessive amounts of weight, which could result in disaster if they are overloaded. The maximum weight limit is based on the limit of each component:

• Semi-tractor
• Trailer
• Tire

Each of these components has a manufacturer-rated maximum weight limit that cannot be exceeded. Most three-axle trucks are not rated for maximum steer and drive axle weights.

For your reference, below is a guide for the maximum tandem permit weight allowed within the United States and Canada:

Download the PDF

Fortunately, tandem-axle trailers aren’t the only solution for heavy freight. Heavier cargo will require a larger trailer with more axles.

What Is the Axle Weight Limit For Tri-Axle Trailers?

As with tandem-axle setups, the weight limits for three-axle trailers, including flatbeds, RGNs and step-decks, vary by state. 

A good rule of thumb is that in most states, a tri-dem trailer can be permitted up to 20,000 pounds per axle, totaling 60,000 pounds. 

However certain states like California, Nevada, Oregon and Washington have significantly stricter regulations for overweight freight movement on three-axle trailers, typically based on axle width and axle spacing. 

It's crucial to be aware of these weight limits and regulations when planning your freight transportation to ensure compliance and safety throughout your journey.

How Much Gross Weight Can You Get on a Tri-Axle Trailer?

The maximum cargo weight you can transport using a tri-axle trailer will depend on the specific regulations of the states you are traveling through. 

Understanding these limits is important for shippers who want to stay in compliance with local laws, and for avoiding future liability for safety and damage issues that can be caused by overloaded vehicles. 

As the number of axles required for your shipment increases, so does the complexity of the process. It is crucial that you work with a knowledgeable provider to guide you through this process. 

Here are the tri-axle weight limits for the contiguous United States and Canada:

Download The PDF

Why Do Axle Weight Limits Matter?

Ensuring the safe and efficient movement of oversize freight is crucial in the trucking industry. Without proper oversight and adherence to legal axle weight limits, there is a higher risk of mishaps and accidents. 

Axle weight limits play a significant role in promoting the well-being of the trucking industry and the motoring public. By regulating the weight distribution on axles, we can maintain safety standards and prevent potential issues that may arise during oversized freight transportation.

Axle Weight Limits Promote Safety

Transporting standard freight shipments can be a challenging task, even under normal circumstances. When it comes to hauling heavier loads, the complexity and difficulty increase exponentially. 

This is especially true for truckers who are responsible for navigating state highways and city streets. Excess weight on the rear axles can make it incredibly challenging to maneuver successfully, especially when turning. 

That's why legal axle weight restrictions play a crucial role in ensuring the safety of the motoring public during the transportation of oversize/overweight goods. Without these restrictions in place, the risk of significant mishaps and accidents harming people and property would be greatly heightened. 

Axle Weight Limits Prevent Damage to Roadways and Equipment

As the weight of a shipment exceeds the standard limitations and pushes the gross vehicle weight beyond 80,000 pounds, the risk of causing damage to equipment and roadways significantly increases.

State, city, and interstate roadways can crack, fray and weaken under the pressure of concentrated masses. State-level per-axle weight limits serve as a crucial safeguard to ensure the preservation and maintenance of roads while facilitating the smooth operation of supply chains.

The owner of the truck and trailer also benefit from per-axle weight limits. The strain placed on trailers carrying overly heavy loads can affect their mechanisms and tires, potentially resulting in permanent damage. Axle weight limits help transportation companies avoid unnecessary maintenance and replacement costs.

Of course, nothing in the trucking industry is easy. Like many other regulations, legal axle weight limits vary by state. 

What Are the Legal Axle Weight Limits in Each State?

Each state sets its own legal axle weight limits. It is important to know the limit for each state on your route before setting out. The best source of information is the Department of Transportation website for each state. The information below, taken from this resource, is provided for your convenience. 

Understand Heavy Haul Regulations Before Shipping Freight

Both state laws and public safety require partnering with a transportation provider who understands heavy haul shipping regulations. Failing to follow these laws will result in additional fees, delays and in some cases liability for damage. 

An experienced shipping provider is also likely to have a fleet of vehicles available to carry even your largest loads safely to their destination. 

After confirming your carrier’s ability to safely move your freight, your next question is probably how much it will cost. Find the answer in What Does Heavy Haul Trucking Cost, which walks you through the cost of shipping overweight loads. 

The Heavy Haul Carrier Selection Checklist can help you find the right heavy haul carrier for your needs. If you’re interested in ATS’ heavy haul services, contact us for a quote.