Having the tractor-trailer weight per axle distribution knowledge is key for any commercial vehicle truck driver because it prevents overweight issues.
Fixing overweight issues is a pain for everybody.
- Owner-operators don’t like being overweight because they may receive tickets from the DOT.
- The National Highway Traffic Safety Administration doesn’t like having overweight trucks rolling on the US roads, highways, and bridges because they are damaging them.
- Company truckers hate returning to the shipper to fix the weight.
To avoid overweight issues, you need to know how to distribute the weight correctly inside a 53ft trailer.
The good thing is that I have already covered this topic below.
What does weight distribution inside a trailer mean?
How much weight per axle can an 18-wheeler carry?
Let's take the example of a semi-truck and a standard 53 foot dry van.
To stay legal with the DOT regulations, without special permits, the gross weight of a loaded tractor-trailer should not exceed 80,000 lbs.
In this case, here is how you figure the trailer’s weight capacity?
- While the truck is empty, go to a truck stop and weigh the rig at a CAT scale.
- Let's say the empty tractor-trailer is 35,000 pounds.
- Now, substract 35,0000 pounds from 80,000 pounds. That leaves 45,000 pounds of available weight capacity for cargo to put on the truck without being overweight on the gross weight.
However, when the trailer is loaded with a heavier load of about 33,000 lbs or more, you may want to weigh the truck because it could be overweight on the axles.
In this case, the first thing to check is that the truck is not overweight on the gross weight of 80,000 pounds.
After that, check the tractor-trailer weight limits by axle:
- Max steering (single) axle on a 53 feet trailer weight is limited to 12,000 lbs.
- Max tandem (double) axle on a 53 feet trailer weight is limited to 34,000 lbs.
Also, the legal weight on the steer axle may change from state to state.
Federal Law states that single axles are limited to 20,000 lbs when spaced more than 40 inches and less than 96 inches from the tandem axles.
So, to stay legal while hauling heavy freight, check the State Oversize Permits & Escorts Information and Requirements.
The actual scaling of the truck
Besides the fact that a standard tractor-trailer has 5 axles, the scaling paper shows weight results on four sets of weights.
These are for:
- the steer axle,
- the drive tandem axles,
- the trailer tandem axles,
- the gross weight of the truck.
The 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
Even though the tractor-trailer gross weight is below 80,000 lbs, it may still be overweight.
That is what happens when the load is not equally distributed inside the trailer.
In the diagram below, you can see the situation when the tractor-trailer is overweight on the drive tandem axles.
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 how 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.