Commercial Drivers must know the Maximum Weight
The allowable gross weight of a bus or truck is determined by tire size, the number of axles, and the spacing of axles (or axles groups).
No vehicle is allowed to operate upon public highways with a gross weight, including load, concentrated on one tire in excess of 600 pounds per inch of width of the tire.
For example, a tire size 10.00 – 22is 10 inches wide and may carry 6,000 pounds. Axles carrying more than 10,000 pounds and equipped with single tires, are limited to 500 pounds per inch of width of tires.
• 20,000 pounds on any single axle, depending on tire size.
• 34,000 pounds on tandem axles spaced less than seven feet apart
• 40,000 pounds for any single-unit vehicle supported by three or more axles.
• 80,000 pounds for any combination of vehicles.