Top 10 Heaviest Semi Trucks in the United States and Canada

Where are the largest trucks operating in the United States and Canada? This is a tricky question, and there are several ways of answering it.  But the commonly reported fact that trucks can only be 80,000 lbs in America is false, there are many trucks that operate at much higher weights on a regular basis. First, it is important to make the distinction between divisible and indivisible loads.

Indivisible loads are usually defined as something that takes more than 8 hours of work to disassemble, so things like heavy equipment and housing units fall into this definition. Most jurisdictions will give a permit to extremely large loads that fit into the ‘indivisible’ category, and some of these trucks and loads can be 250,000 lbs or more.  This article will not talk about these combinations, as they are special cases and usually fall under exceptional laws.

Divisible loads are loads that can be separated into smaller loads in less than 8 hours of work, which means pretty much everything, like cola or beer, popcorn, processed metals, grains, etc, etc.  In fact, the vast majority of items that you as a consumer and industry uses everyday are ‘divisible’.

Sometimes trucks can have higher gross weights than 80,000 lbs without a permit and still carry a divisible load, some states and provinces require a permit, but this just means a little extra paperwork.

So where can the largest divisible loads be carried on regularly operating trucks?  We have assembled a list of the largest trucks operating regularly, carrying divisible loads and they are:

Among the heaviest regularly operating trucks in North America, this South Dakota truck has 17 axles and can gross out at over 170,000 lbs. Thanks Norseman at Hank’s Truck Pictures for the picture!


1. South Dakota Non-Interstate Roads 171,000 lbs / 77,564 kgs
Many may think that Michigan has the heaviest trucks in North America, not this is not true. South Dakota has no gross weight limit on non-interstate roads, and no limit on the number of axles you can put under a truck, it just has to follow the bridge formula, and get a permit for truck over 80,000 lbs. Pull double trailers each 45’ feet long, and you can fit a lot of axles under a truck.  The truck pictured above has 17 axles and can gross out at about 170,000 lbs.

2. Michigan Octopedes (8 axle trailers) and Double Trailers: 154,000 – 164,000 lbs / 69,853 – 74,389 kgs
In Michigan, grandfathered laws allow the use of very heavy truck combinations. They can go up to 164,000 lbs with the correct axle spacings, and combinations can have a maximum of 11 axles. Commonly, trucks of this size are used to haul steel, aggregates and other bulky materials. Because these are grandfathered laws, these truck combinations are allowed to operate on the interstate. But truckers need to watch out because axle weights are actually lower than according to ‘federal laws.’ A extra permit is not required for these vehicles.

3. Quebec Long Combination Vehicles: 148,812 lbs / 67,500 kgs
La Belle Province has increased weight limits for Long Combination Vehicles (LCV)’s over the weights normally allowed for most other trucks in Canada. In Quebec, turnpike doubles can be operated on divided highways, have two trailers each being 53’ long. Permits are required for these LCVs, as well as extra training for the drivers.

4. New York Long Combination Vehicles: 143,000 lbs / 64,864 kgs
New York allows turnpike doubles on the thruway with a cargo carrying length of 102’, which means the distance from the front of the first trailer to the back of the rear trailer. These trucks are not allowed to operate off of the thruway and there are staging yards set up, usually close to toll booths, where the second trailer can be attached to the first trailer. Extra permits are required.

5. Canadian B-Trains and Long Combination Vehicles: 139,993 lbs / 63,500 kgs
Across Canada, B-Trains can operate at the high weight of 139,993 lbs. These combinations typically have 8 axles and are put to work carrying almost everything. B-Trains in Canada require no extra driver training or permit, unlike in the US where you have to have an extra driver training certificate to operate double trailers.  The picture below is of a nice Canadian B-Train.

Canadian LCVs in the provinces of British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, New Brunswick and Nova Scotia can all operate at the same total gross weight as well, although these long combinations, typically 2 x 53’ trailers require permits.

Canadian B Train carrying Lumber Big Truck Guide
Canadian B – Train carrying lumber – Source: Hank’s truck pictures

6. Ontario – 8 and 9 axle semi trucks 139,993 lbs / 63,500 kgs
In the Canadian province of Ontario, tractor trailers that have the appropriate number of axles and axle spacings can reach the same maximum weights as B-Train combinations. These trucks usually have ‘steerable’ axles on the trailer so that it can turn corners. Older trailers have ‘lift’ axles that drivers must lift up and down every time they make a turn. No special permits are required, your truck must be licensed for the extra weight though!

7. Alaska – Long Combination Vehicle with Triple trailers 138,000 lbs / 62,596 kgs
Alaska is the second of 2 states in the United States that have no gross weight limit, you are just required to comply with bridge formulas. This means that the truck’s axles must be spaced far enough apart and carry less weight the closer the axles are to each other. This formula is called the bridge formula because it helps to protect bridges from damage by overloaded trucks. The weight given here as an example is an estimate of an 11 axle LCV that is long, it has 3 trailers that have a combined length of 110’. Other trucks may carry more weight in Alaska because there is no gross weight limit!

8. Montana B-Train 137,800 lbs / 62,142 kgs
Montana has some heavy trucks permitted on its roads, but this is the heaviest allowed in the state. It is a Canadian B-Train that is allowed to cross the border from Canada and travel to the town of Shelby, just across the border. A permit is required for this truck.

9. Utah – Long Combination Vehicles 129,000 lbs / 58,513 kgs
Utah has high permitted weights for its Long Combination Vehicles, and trucks with over 81’ of trailers, usually operating as a Rocky Mountain Double can get weights of up to 129,000 lbs. These combinations must have a LCV permit and are only allowed on certain roads.

10. Idaho 8 Axle B-Train 129,000 lbs / 58,513 kgs
The same combination that can obtain weights of 139,993 lbs in Canada can get the still very respectable gross weight of 129,000 lbs in Idaho. However, there is the tricky situation where this same truck can only carry 105,000 lbs on the interstate, which is the grandfathered weight in the state, but is allowed to carry more weight on state roads.

If you would like to obtain more information on these truck combinations, please see our truck weight tools like the Detailed Truck Information page.  Thanks to Hank’s truck pictures for the pictures in this post!

6 thoughts on “Top 10 Heaviest Semi Trucks in the United States and Canada”

  1. Being from Arizona in certain areas of the state we allow triple trailers.B trains. Rocky mtn doubles. LCV’s.I-15 is one area.and at the top of the state entry is allowed with in 20 miles within the border.

  2. That’s right, and in the Big Truck Guide membership site, you can find all the legal combinations in every state, including Arizona. We have the legal weights on all LCVs allowed in Arizona, including Doubles, Rocky Mountain Doubles and Triple trailer Combinations. Membership Options!

  3. In South Dakota my friend class he saw a 21 axle flatbed hauling pipe. How can that be legal?????.

  4. Hi! Its legal cause South Dakota has no maximum gross weight limit, you just have to comply with the US Federal Bridge formula for axle weights, and there is no limit on the number of axles. So you can get some really big big trucks 🙂

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