Owner-operators don’t like being overweight because they may receive tickets from DOT.
The National Highway Traffic Safety Administration don’t like having overweight trucks rolling on the US roads, highways, and bridges because that damages them.
Company truckers hate finding out that they have to return to the shipper to fix the weight inside the trailer.
To avoid overweight issues, you need to know how the weight needs to be legally distributed on an 18-wheeler.
The good thing is that I cover this below.
What does weight distribution inside a trailer mean?
The weight distribution inside a trailer is the act of spreading the total gross weight between the tractor-trailer axles.
This act ensures that the imposed weight on the ground doesn't worsen the quality of the US roads.
How much weight per axle can an 18-wheeler carry?
The standard maximum gross weight of the tractor-trailer combination should not exceed 80,000 lbs.
From here, let’s break it down to how much weight should go per axle to stay legal with the DOT weight regulations.
- Max steering axle weight is limited to 12,000 lbs.
The steering axle is the axle controlled by the driver, which gives the direction traveled by the vehicle. It may change from state to state.
Federal Law states that single axles are limited to 20,000 lbs and spaced more than 40 inches, and not more than 96 inches apart (tandem axles) are limited to 34,000 lbs.
- Max single axle on a 53 feet trailer is limited to 20,000 lbs.
- Max tandem (double) axle on a 53 feet trailer is limited to 34,000 lbs.
However, the axle weight limits may range from state to state. So, before you start rolling, make sure to check the State Oversize Permits & Escorts Information and Requirements to stay legal while hauling.
Knowing the maximum weight limits on a tractor and a semi-trailer helps to understand when the truck is overweight.
The actual scaling of the truck
Even though, a tractor combined with a 53-feet semi-trailer has five axles, the scaling paper shows the weight on three sets of weights. These are the single steer axle, the drive axles as a set, and the trailer tandem axles as a set.
The tricky thing is that even when the tractor-trailer doesn’t exceed the max gross weight limit of 80,000 lbs, it still can have overweight issues.
The trick with the max gross weight limit
Generally, the legal weight for a 53 feet semi-trailer combined with a tractor is 80,000 lbs.
However, even though the tractor-trailer gross weight is below the 80,000 lbs, it may still be overweight.
That happens when the load is not equally distributed inside the trailer.
For example.
In the diagram below, you can see the situation when the tractor-trailer is overweight on the drive tandem axles.
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Methods of redistributing the weight inside the trailer
In case when the truck is overweight on one of the axles, here are a few ways to distribute the weight inside a trailer:
- Redistribute the weight inside the trailer back and forward.
- Slide the 5th wheel.
- Slide the trailer tandem axles.
- The amount of fuel onboard and the placement of the fuel tanks may also affect the weight distribution inside the trailer.
Weight distribution inside the trailer doesn't affect the truck's gross weight
While you distribute the weight inside the 53 foot trailer, the gross weight remains the same.
That is an important thing to keep in mind.
The only way to affect the gross vehicle weight would be to burn fuel, remove extra weight from the trailer, or redistribute the weight inside the trailer.
