Simplify Your Oversize/Overweight Loads
Max Legal Weight for GVW under 80,000 lbs and Max Permitted Weight for GVW over 80,000 lbs
The maximum gross vehicle weight on the interstate highway system is 80,000 pounds.
The gross vehicle weight of any vehicle or combination of vehicles is determined by the following weight formula of:
where W equals maximum weight in pounds carried on any group of two or more axles; L equals distance in feet between the extremes of any group of two or more consecutive axles; and N equals number of axles in the group under consideration except that two consecutive sets of tandem axles may carry a gross load of 34,000 pounds each, providing the overall distance between the first and last axles of the consecutive sets of tandem axles is at least 36 feet.
The maximum gross vehicle weight on state highways is 105,500 pounds unless otherwise posted. On all other highways the maximum gross vehicle weight is 80,000 pounds unless designated for more, not to exceed 105,500 pounds.
The gross vehicle weight of any vehicle or combination of vehicles is determined by the following weight formula of:
where W equals the maximum gross weight in pounds on any vehicle or combination of vehicles; L equals distance in feet between the two extreme axles of any vehicle or combination of vehicles; and N equals the number of axles of any vehicle or combination of vehicles under consideration.
Steering axle: the weight shall be determined by the manufacturer’s axle rating and shall not exceed 20,000 pounds when travel:
On the state system, the gross weight shall not exceed 20,000 pounds.
No tire shall exceed 550 pounds per inch of tire width.
No single axle shall carry a gross weight in excess of 20,000 pounds. Axles spaced 40 inches or less apart are considered one axle. Axles spaced 8 feet apart or over are considered as individual axles. (The gross weight of two individual axles may not exceed 40,000 pounds on highways other than the interstate system.) On the interstate system the gross weight of two individual axles may be restricted by the weight formula. Spacing between axles shall be measured from axle center to axle center. The weight per inch of tire width shall not exceed 550 pounds.
Axles spaced over 40 inches apart and less than 8 feet apart shall not carry a gross weight in excess of 19,000 pounds per axle. The gross weight of a tandem axle may not exceed 34,000 pounds. The gross weight of three or more axles in a grouping may not exceed 48,000 pounds on highways other than the interstate system. On the interstate system the gross weight of three or more axles is restricted by the weight formula. The weight per inch of tire width shall not exceed 550 pounds.
The maximum weight on a tandem axle is 40,000 lbs. and a single axle is 22,000 lbs. when the GVW exceeds 150,000 pounds.
Axle weight limitations for vehicles and vehicle combinations, e.g. truck, truck-tractor and semitrailer transporting a load or towaway, are subject to the following maximum permitted axle weights:
600 pounds per inch of tire width is allowed on the steering axle when:
Single and tandem axle weights may not exceed 600 pounds per inch width of tire. A group of three or more axles may not exceed 550 pounds per inch width of tire.
Source of information: https://www.nd.gov/ndhp/sites/www/files/documents/Permits/9-1_handout.pdf
https://www.nd.gov/ndhp/oversizeoverweight-permit
https://www.nd.gov/ndhp/sites/www/files/documents/Permits/9-6%20handout.pdf