Truck Driver's Guidebook
Bridge Gross Weight Formula

Back | General Bridge Formula Info

This 5 axle tandem tandem has an outer bridge of 46' (distance between axles 1 and 5). Using the B/F, this tandem tandem would be allowed a gross weight of 76,500 lbs. If this combination exceeds the gross weight of 76,500 lbs., it would be in violation. Also, the inner bridge on this vehicle is 36' (distance between axles 2 and 5). Using the B/F, this group of axles would be allowed a group weight of 66,000 lbs. If this group exceeds the weight of 66,000 lbs., the group would be in violation.

This 5 axle tandem tandem has an outer bridge of 54' (distance between axles 1 and 5). Using the B/F, this tandem tandem would be allowed 81,500 lbs. But, the B/F only allows vehicles up to a gross weight of 80,000 lbs.  If this 5 axle tandem tandem exceeds 80,000 lbs. gross weight, it would be in violation. The inner bridge on this tandem tandem is 42' (distance between axles 2 and 5). Using the B/F, this group of axles would be allowed a group weight of 70,000 lbs. However, if the group weight exceeds 68,000 lbs., it would be in violation because each tandem is allowed 34,000 lbs.

Back | General Bridge Formula Info

***The bridge formula allows up to 20,000 lbs. per single axle, if the vehicle is equipped with large enough tires.  Steering axle weights will vary depending on the gross weight of the vehicle.

Due to frequent changes in federal and state regulations, the Michigan Center for Truck Safety cannot ensure the accuracy of the material contained in the Guidebook beyond the date of publication. For current information, contact the Center at (800) 682-4682. This document is not intended for legal purposes.