To get the answer, you need to weigh your tractor trailer empty. When you get that weight, Lets talk numbers, this is wrong but it is a big example. If your tractor trailer is 35,000 pounds empty....
To be legal for interstate travel with no extra permits the legal limit is 80,000 lbs. 20,000 lbs on single axles, 34,000 on dual axles. 12,000 on the steer axle .