As core stakeholders of the transportation industry, it’s not uncommon for shippers, like you, to have questions about transportation’s many facets.
- How many pallets typically fit in a dry van trailer?
- How much overhang am I legally allowed on a flatbed trailer?
- Is it possible to shave some dollars off my freight rates?
The answers to these, and questions like these, can sometimes feel hidden in the fast-paced world of transportation and leave you feeling undervalued, unseen and forgotten.
Recently, your questions regarding the legal axle weight limits for freight transported on tandem-axle and tridem-axle trailers have been unanswered – leaving you without direction once more.
With something as important as the health of your company’s supply chain on the line, you deserve much better from the transportation businesses that keep America’s industries afloat.
Here at Anderson Trucking Service (ATS), we have an extensive fleet of semi-trailers and a deep knowledge of the rules and regulations that accompany running them.
While the total amount of axle weight your shipment will be allowed varies both by time of year and across state lines, an understanding of these things will do you well in the future.
In this article, you’ll find an in-depth overview of:
- The legal maximum gross vehicle weight for semi-trucks.
- When axle weight limits become a factor.
- What the axle limitations are for tandem-axle trailers.
- What the axle limitations are for tri-axle trailers.
- Why legal axle weight limits really matter.
At its conclusion, this article will remove a lot of confusion from this process and leave you far better suited to plan your loads according to legal axle weight limits.
What Is The Legal Maximum Gross Vehicle Weight For a Semi-Truck?
According to the federal government’s gross vehicle weight guidelines — without permitting — semi-trucks and the loaded trailer behind them can weigh no more than 80,000 pounds collectively.
This 80,000-pound limit governs the movement of all multi-piece freight shipments — like loads of steel I-beams — which can be evenly distributed, yet still pose a risk of equipment damage and safety concerns.
The percentage of these 80,000 pounds — which includes the overall curb weight of each semi-tractor — that’s dedicated to hauling your freight will change based on the weight of your truck and trailer combo when “empty.”
Dry van trailers, for example, weigh more than flatbed and step-deck trailers. Though this added heft can be attributed to the fiber-glass encasement, keeping van freight protected from the elements in transit, it also means that dry van trailers allow less load weight than other trailer types.
Beyond solely dry vans, the construction of many trailer types will also vary, decreasing or increasing their overall weight accordingly.
For your reference, here are some general freight-weight thresholds for the three most common, tandem-axle trailer types:
- 53-foot refrigerated trailers can usually haul between 43,000 to 45,000 pounds.
- 53-foot flatbed trailers can typically haul between 45,000-48,000 pounds.
- 53-foot dry van trailers can typically haul between 43,000-46,000 pounds.
With these ranges accounted for, the remaining 32,000 (or so) legally-allotted pounds must be dedicated to the tractor pulling every load. But how much weight — which must be properly distributed — should a semi truck’s axles (one steer and two drive) respectively bear?
What is the Weight Limit for Steer Axles?
The steer axles — located at the front of a semi-truck — typically hoist 12,000 to 15,000 pounds (or 6,000 to 7,5000 pounds on each tire). This total, however, may fluctuate slightly depending on the make and model of the vehicle in question and the overall weight distribution of the load.
What is the Weight Limit for a Semi’s Drive Axles?
To land within the federally-allowed 80,000 total pounds of gross vehicle weight, the two drive axles of a class-8 semi-tractor typically hold no more than 34,000 pounds.
Broken down further, this 34,000 pounds is distributed at 17,000 per axle and 4,250 pounds for every tire.
When Do Legal Axle Weight Limits Come Into Play?
For single-piece freight shipments that exceed the legally allotted 80,000 pounds of gross vehicle weight, overweight permitting must be acquired from each state, city and/or township it’s traveling through.
It’s at this point that legal axle weight limits also come into play.
States define the thresholds for single, tandem and tridem-axle freight movement on an individual basis. Let’s talk about them.
What Is The Axle Weight Limit For Single-Axle Trailers?
According to federal rules and regulations, the maximum amount of cargo weight for single-axle transportation equipment is 20,000 to 25,000 pounds. This limit applies to one-axle trailers, boosters and stingers. Anything above this weight risks damage to roads, bridges, cargoes and the safety of the motoring public
To haul freight exceeding 20,000 pounds, an additional axle — with appropriate spacing (which can vary by state) — will need to be utilized.
What Is The Axle Weight Limit For Tandem-Axle Trailers?
Tandem-axle trailers, where each axle is spaced no less than 45 inches and no more than 96 inches apart, can legally haul 34,000 pounds on two axles. Coupled with its semi-tractor’s two drive axles, standard tandem-axle trailers (such as step-decks and flatbeds) can get up to 48,000 pounds of weight without needing to permit.
That said, every state sets different boundaries for the tandem-axle loads that exceed these thresholds.
As a general rule of thumb — when looking to transport overweight, single piece, freight through the majority of states — you should be able to get anywhere from 22,000-25,000 pounds per axle on your tandem-axle trailer through permitting.
Although it’s important that you consult an experienced transportation provider before moving overweight freight, you can expect to be allowed 22,000 pounds per axle (44,000 total) for these loads in the majority of states.
For your reference, here are the legal total cargo-weight thresholds for tandem-axle trailers across the United States and Canada:
How Much Gross Weight Is Allowed On a Tandem-Axle Trailer?
When you have a single piece of freight to move, it’s possible to exceed a gross vehicle weight of 80,000 pounds — with the right due diligence and proper permitting.
The total amount of weight you can carry on your tandem-axle trailer will depend, primarily, on which state(s) your load needs to traverse and the construction of the equipment used to do so.
Once you’ve selected your route and have acquainted yourself with the tandem axle weight limitations of each state you’ll interact with, this problem becomes easier to solve.
For example, let’s say you need to move freight through North and South Dakota.
Both of these northern states allow 44,000 pounds on tandem-axle trailers.
Coupled with the 34,000 pounds offered by the drive axles and the 12,000-15,000 offered by the steer axle on the semi-truck hauling your load, you could haul up to 93,000 pounds of gross vehicle weight on this shipment with proper permitting.
It should be noted that although the weight of your load doesn’t need to be evenly distributed, the weight placed on each axle grouping cannot exceed legal limits.
Additionally, just because a state gives you the legal ability to haul an excessively heavy load, doesn’t mean that your trailer will be capable of doing so. Many tandem-axle trailers simply aren’t constructed to bear excessive amounts of freight weight, leading them to become compromised under too much heft.
What Is The Axle Weight Limit For Tri-Axle Trailers?
Like tandem-axle setups, the allowed per-axle limits for three-axle trailers (such as flatbeds, RGNs and step-decks) vary by state. Generally, states east of the Mississippi River give shippers more leeway when it comes to axle weight limits than their western counterparts.
As a general rule of thumb, 20,000 pounds per axle (60,000 pounds total) on a tridem trailer will be permissible in the majority of states.
That said, states like California, Nevada, Oregon and Washington — to name a few — restrict overweight freight movement on three-axle trailers substantially, with California only allowing 51,000 total pounds — 17,000 per axle.
Here are the tri-axle weight limits for the conterminous United States and Canada:
How Much Gross Weight Can You Get on a Tri-Axle Trailer?
The total amount of cargo weight you can haul using a tri-axle trailer will depend, once again, on the individual regulations of the states you’re traveling through.
As the number of axles necessary for hauling your shipment increases, so too does the complexity of doing so. For this reason, it’s important that you work with a competent provider to assist you through this process.
To highlight how you could potentially approach this though, here’s a look at another scenario:
Let’s pretend your shipment needs to be transported within Texas from Houston to Dallas.
Texas, like many other states, restricts tandem-axle freight to 20,000 pounds per axle — or 60,000 pounds total. As such, in this example, you’d want to ensure that no more than 60,000 pounds collectively rests on the three axles of your selected trailer.
In addition to this, the two drive-axles of the truck pulling your load will give you an additional 34,000, or so, pounds of payload to work with.
Since axle-calculated weight limits don’t necessarily need to be evenly distributed — as long as the per-axle weight limits aren’t surpassed — this 94,000 pounds can be utilized in a number of ways, depending on where the weight is centered on the piece you’re moving.
For this reason, it’s not unreasonable to get 58,000 pounds on the trailer axles and 35,000 on the drive axles.
Why Do Axle Weight Limits Matter?
Oversized freight movement isn’t always easy. Without proper oversight and regulation, this process could easily go wrong; causing mishaps across the board. That said, there are two primary reasons that legal-axle weight limits matter greatly to the wellbeing of the trucking industry and the motoring public. . .
1. Axle Weight Limits Promote Safety
Hauling standard freight shipments, of normal weight, can be challenging at the best of times. Adding more heft to a load, only complicates this process further.
For truckers, responsible for maneuvering shipments along state highways and city streets, heavy shipments make it more difficult to do so successfully — especially with too much weight on a trailer’s rear axles.
As such, legal axle weight restrictions keep the motoring public safe from harm during the transportation of oversized goods. Without them, significant mishaps could occur.
2. Axle Weight Limits Prevent Damage to Roadways and Equipment
As the weight of a shipment arches beyond standard limitations, dragging gross vehicle weight beyond 80,000 pounds, the possibility of equipment and road damage increases substantially.
Overly heavy loads are taxing on the trailers that carry them, stressing their mechanisms and tires in ways that can cause permanent damage. Axle weight limits help transportation companies avoid unnecessary maintenance and replacement costs.
Additionally, state, city and interstate roadways are highly susceptible to cracking, fraying and weakening due to highly-concentrated mass.
State-level per-axle weight limits help governing bodies keep their roads in good condition while keeping supply chains running smoothly.
Got More Questions About Heavy Haul Trucking?
The world of heavy haul freight movement is complex, to say the least. With so many rules and regulations to keep in mind and companies to choose from, it’s not unreasonable if you feel intimidated.
Here at Anderson Trucking Service, we pride ourselves on helping shippers, just like you, get the most from their transportation decisions — especially as they relate to heavy haul.
The most common questions these companies come to us with are centered around, “what will this cost?” Unfortunately, many transportation providers don’t answer price-related queries as transparently as they should. That said, today you’ll get the answers you’re looking for.
Check out our article “What Does Heavy Haul Trucking Cost” for an in-depth overview of the main factors that impact your pricing and what you should expect to pay.
Finally, if you have any other questions about heavy haul trucking, including what trailer combinations are used for it or what you can do to cut down on costs, please don’t hesitate to reach out. We’re happy to assist you in any way you need.