Pennsylvania Axle Weight Limits

Every truck shall have its own registered gross weight based on the gross vehicle weight rating assigned by the manufacturer (specified on the federal weight certification label) and an equivalent weight rating determined by PennDOT based on axle and wheel strength, horsepower, baking power and other factors affecting the ability of the vehicle to handle heavier loads.

If the farm vehicle is registered, no truck may be operated with a gross weight in excess of its registered gross weight. No combination containing a trailer having a gross weight or registered gross weight in excess of 10,000 pounds shall be operated with a gross weight in excess of the registered gross weight of the truck or truck tractor for a combination.

The maximum weight of any individual vehicle, including farm vehicles, is 80,000 lbs. The maximum gross weight of any combination is 80,000 lbs. These limits are subject to the registered gross weight of the vehicle, requirements regarding axle weight and requirements regarding wheel load. Vehicles are also subject to any weight restrictions applied to particular roads or bridges. 

Combination of vehicles - No combination shall, when operated upon a highway, have a gross weight exceeding the following:

• Two-axle truck tractor & single-axle semitrailer - 58,400 pounds;
• Two-axle truck & two-axle semitrailer - 73,280 pounds;
• Three-axle truck tractor & single-axle semitrailer - 73,280 pounds;
• Two-axle truck & two-axle trailer - 73,280 pounds.

Maximum Axle Weight of Vehicles

No vehicle or combination driven upon a highway shall have a weight upon any axle in excess of the lesser of the manufacturer's rated axle capacity or the following applicable weight:

• Steering Axles - 20,000 pounds, 
• Single Axles - 20,000 pounds;
• Tandem Axles, a.s. under 6 feet - 36,000 pounds;
• Tandem Axles, a.s. 6 to 8 feet - 40,400 pounds;
• Tandem Axles, a.s. over 8 feet - 44,800 pounds;
• Tridem Axles - 42,500 pounds.

No combination registered and carrying a gross vehicle weight in excess of 73,280 pounds shall have an overall gross weight on any single axle, other than the steering axle, in excess of 20,000 pounds, or an overall gross weight on any group of two or more consecutive axles in excess of that produced by application of the following formula:

W = 500(LN/(N - 1) + (12N + 36))

where

W = overall gross weight on any group of two or more consecutive axles to the nearest 500 pounds,
L = distance in feet between the extreme of any group of two or more consecutive axles,
N = number of axles in group under consideration, except that two consecutive pairs of axles may carry a gross load of 34,000 pounds each, provided the overall distance between the first and last axles of such consecutive pair of axles is 36 feet or more.

When a truck tractor is registered in excess of 73,280 pounds and its operating in combination with an overall gross weight of 73,280 or less, maximum axle weights shall be applicable for the purposes of weighing the combination.

Maximum Permit Weight Allowed

Maximum allowable axle weight of vehicles are the following: 

• Single Axle - 27,000 pounds;
• Tandem Axle - 52,000 pounds.

A Single Permit may be issued for a number of movements across the highway at specified locations within a fixed period of time of vehicles or combinations:

1. exceeding the maximum size or weight specified in this chapter; or 
2. used to cross a highway to get from one commercial or industrial facility to another commercial or industrial facility under the same operation.

Whenever a permit is issued for crossing the highway, it is unlawful to move the vehicles along the highway.