Tractor Trailer Weight Per Axle

By Max Anthony •  Updated: 01/16/23 •  5 min read

Tractor Trailer Weight Per Axle

Why Do Axle Weight Limits Exist?

In 2018, US state and local governments spent more than $187 billion on highways and bridges, making it the fifth largest spender. 44% of these funds went to maintenance and the remaining 56% went to the actual construction of the roads and highways.

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Most road and bridge damage is caused by heavy vehicles. This is because as axle weight increases, road damage quadruples instead of increasing linearly. In other words, changing from a 1-ton axle to a 5-ton axle causes 625 times more damage to the road surface. That is why there are strictly adhered total weight and axle weight limits.

Why are Axle Weight Limits Important To Truckers?

The simplest answer to this question is huge fines. Road repairs cost the state a huge amount, so the costs are passed on to you. If you get caught with overweight axles or gross vehicle weight, or worse, if you haven’t purchased an overweight permit, the consequences can be devastating.

Severely overweight vehicle fines can run into the tens of thousands of dollars, and when overweight fines are imposed, it is the driver who is quoted and has that notice on their driver’s license. Most states also add court costs, which can double the total cost of a fine. See here for a summary of overweight fines by state.

Additionally, most states classify violating obesity limits as a misdemeanor, not a felony, but subject to probation, community service, and/or imprisonment ranging from a few weeks to a year. Remember that trying to circumvent the limit by falsifying the weight of an overweight card can be a crime.

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Therefore, it is important that both drivers and dispatchers are aware of the truck’s capacity and weight limits for axles and axle groups, even before receiving a shipment.

These weights vary from state to state, and many variables are used to determine the maximum allowable weight, not just the gross vehicle weight or 20,000 per axle. They’re very complicated and take time to figure out, but you have to somehow understand them before the violation is recorded on the record and you pay a fine of thousands of dollars.

How are Axle Weight Limits Determined?

You can’t carry more than your gear can handle. Both the truck and trailer should have a manufacturer’s rating. Make sure your weight is below these limits.

Remember, just because your gear can handle weight doesn’t mean your state will allow you to carry it. This also applies to the tire rating.

There are two limits that need to be considered. legal maximum and permissible maximum.

The maximum permissible axle load is the weight that can be moved without a purchase permit. Below federal bridge official or state legal axis limits (state limits are often higher than federal limits).

Tractor Trailer Weight Per Axle

The maximum axle weight allowed is the weight the state will not allow you to move even if you have a permit. Always be aware of these two restrictions for the states you pass through.

There is only one federal regulation regarding the legally permissible maximum weight. The federal government does not issue inspection permits. That is, there are no maximum limits set by individual federal states.

Here are the federal restrictions you need to be aware of:

Pretty much everything else you need to know about is state level regulation.

What are State Axle Weight Limits?

State borders are of utmost importance because they determine how far and if you can travel within that state. Again, there are two numbers you need to know. Legal weight limit and maximum weight allowed.

Given these two numbers, there are three ranges. For example, in Texas, the legal maximum weight for a tandem is 34,000 lbs and the maximum allowable weight is 46,000 lbs. This means that without purchasing a permit you can load a tandem up to 34,000, with a permit you can load up to 34,000-46,000, and if you load over 46,000 you will not be able to enter Texas.

Note that states do not normally issue overweight permits for split luggage. That said, you can technically hold up to 46,000 lbs on your tandem if you buy a permit, but if you can easily unload the extra weight (e.g. if you’re hauling sand or gravel haulage).

Most states do not issue that permit. The overweight allowance applies to packages that cannot be split. For example, mechanical parts that cannot be easily disassembled for weight reduction. Of course, there are exceptions and special permits for divisible loads, which must be coordinated with the states.

The legal maximum weight for each axle is determined by the Federal Bridge Formula, the federal limits for single axles and axle groups, and the individual axle and axle group legal limits issued by each state. Take note that state boundaries are often higher than federal boundaries.

To calculate the maximum allowable weight for an axle or axle group, a few things are required.

The two most important considerations when determining the maximum allowable weight are:

1) tire weight limits, and 2) single axle and axle group limits. Both limits must be known and the lower limit determines the maximum allowable weight.

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Max Anthony

Max is a gizmo-savvy guy, who has a tendency to get pulled into the nitty gritty details of technology and cars. He attended UT Austin, where he studied Information Science. He’s married and has three kids, one dog and a GMC truck and a Porsche 911. With a large family, he still finds time to share tips and tricks on cars, trucks and more.