multiple axle rigs

For the most part yes. My setup is 7 axles & is about 44,500 lbs empty. I can't load very much weight to be legal, but I can gross out at 132,000 lbs.

 

Yes they are overweight when loaded. You can buy permits for the weight, but will still have limits to what each axle can carry.

 

I think that depends on the state, I believe that some states will issue a annual permit while others will just let you register for the weight.

 

In any situation the gross goes over 80,000 it should be permitted. They may have a single trip permit or an annual permit depending on the situation. In the setup you described they would surely be permitted because there would be no reason to have a setup with extra axles & not be hauling heavy. That would be a lot of extra expense for extra axles, tires, weight, fuel, etc. for no reason.

 

I use to haul livestock with a triple axle trailer, I was registered for 86,000 in Iowa, but was not allowed to run the interstate over 80,000.

 

Alaska bridge law says I can haul 92000 with three axle side dump and tandem tractor, unless weight restrictions are on in the spring. That is overall length and number of axles, I will try to find the formula the state uses.

 

Multi-axle extended weight trucks have permits. Each state can vary. Bridge laws play a big part in extended weight trucks. Tri/quad groups or spreads all have designated weights formulated by distance between axles blah blah blah. Then there's H.H. and super permits.

 

Hi p47, Michigan "doubles" are an impressive sight. I have a hard time posting pictures here, but if you google image it, you'll see. The law says you can have a GVW of 164,000 lbs. spaced through 11 axles at 13,000 lbs each. They are popular with mining dump trucks and stick haulers. I have the utmost respect for those drivers.