Big rigs are limited by federal regulation to a maximum loaded weight of 80,000 pounds including cargo. The type and weight of the truck when empty changes how much can be carried.
Generally speaking, cargo payloads for big rigs or 18-wheelers are as follows:
Flatbed trailers: can load up to 48,000 pounds of cargo
Dry vans trailers: 44,000 to 45,000 pounds
Refrigerated trailers or reefers: 42,500 to 44000 pounds.
NOTE: I proved that the Tesla Semi showed it can move at least 44,000 pounds of cargo on a flatbed trailer.
The reason for the different payloads across the three most common trailer types is the weight of the trailer. Flatbed trailers are usually made of aluminum and as such are very light offering the highest possible payload within the 80,000-pound maximum limit. Dry vans have more to them including a fiberglass body on top of the trailer adding weight and reducing the payload by a few thousand pounds. Refrigerated trailers are even heavier than dry vans as they require insulation inside the fiberglass walls to keep freight cool or frozen plus they have to carry a massive refrigeration motor on the front of the trailer and an extra diesel tank under the trailer.
The maximum amount over each of the three axles groups (one steer axle and two tandems) is as follows:
Steer axle: 12,000 pounds or 6,000 pounds per tire
Drive axle tandems: 34,000 pounds or 4,250 pounds per tire
Trailer tandems: 34,000 pounds or 4,250 pounds per tire.
Individual states also have additional weight carrying limits for intrastate commerce. Heavier loads based on additional axles being installed. To carry higher weights though, the truck axle specification and rating must allow for the heavier weights to be carried. These include:
Rocky Mountain Doubles – a tractor with two trailers: a long front trailer (usually 48 feet) followed by a shorter second trailer – maximum weight up to 129,000 pounds
Turnpike Doubles – a tractor and two long (usually 48 feet) trailers – maximum weight up to 147,000 pounds
Triples – a tractor and three short trailers (usually 28 feet) – maximum weight up to 110,000 pounds
Michigan Octopodes – 8-axle double trailer combinations weighing up to 164,000 pounds.
Truckers in Europe can load 88,000 pounds and usually run 6-axle combinations with tri-axle trailers.
Canadian weight regulations are set by each province based on the number of axles and specifications of the truck. Canadian B-Trains are 8-axle combinations with two trailers that can weigh a maximum of 140,000 pounds and in Ontario 9-axle big rigs can also gross 140,000 pounds.
* 36,000 pounds for two-axle trucks
* 50,000 pounds for three-axle trucks
* 62,000 pounds for double-steering axles and four-axle trucks
* 72,000 pounds for four-axle combination vehicles
* 86,000 pounds for five-axle combination vehicles
* 98,000 pounds for six-axle combination vehicles.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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