It can be complicated - in the US:
There are one set of rules that are set by the US Federal government and they say that for highways that are federally funded (interstates and some other bigger roads) the minimum weight that states HAVE TO allow is 80,000 lbs.
States cannot set the limit on interstates lower than 80,000 lbs, but they can set lower limits on state highways. However, there is a catch.. if a state had a higher weight limit in place before this federal law was passed (Surface Transportation Assistance Act of 1982 (STAA)) the state can still allow trucks heavier than the 80,000 lbs limit. The state with the highest weight limits by far is Michigan. The highest grossing truck without a permit in Michigan can top out at 151,400 lbs! With 8 axles on the trailer! Without a permit! Usually these trucks carry loads of raw steel between steel mills and factories.
In Canada, most of the country allows much higher weights than in the US (but not as high as Michigan). Each province sets their own weight limits independently. A typical combination in Canada is a tandem drive tractor with a tri-axle trailer. This is like the typical 18 wheeler with an extra axle on the trailer (22 tires). Weights vary across the country but they are usually around 110,000 lbs. The second usual combination that is used across Canada is the B-Train. It is a tandem drive tractor pulling a trailer with three axles, and attached to this trailer is a second trailer with two axles. Across Canada, the B-Train weight limit is 139,700 lbs (63,500 kgs).
Paul at www.bigtruckguide.com
· 6 years ago