Axle load – everything you need to know about it

How to calculate axle load

To understand how to calculate axle load, you first need to know the weight of the vehicle and how that weight is distributed among the individual axles. In practice, each vehicle data plate contains information about the maximum load on the front and rear axles, specified in kilograms. This data allows drivers and mechanics to assess whether a vehicle is properly loaded.

What information does the vehicle data plate contain?

The data plate is usually located under the hood or on the vehicle’s pillar, although it depends on the vehicle you have. The plate contains data such as the VIN (vehicle identification number) and load values ​​for the front and rear axles. This information is needed for the proper operation of the vehicle and to avoid overload.

Differences between drive and non-drive axles

• Axle function: the drive axle is responsible for transmitting torque from the engine to the wheels, which allows the vehicle to be propelled. The non-drive axle does not transmit torque, its main function is to support the vehicle’s weight and increase stability.
• Load: Drive axles are typically designed to withstand greater loads than non-drive axles. Thanks to this, they can effectively transmit the driving force while withstanding greater pressures from the weight of the vehicle and cargo.
• Suspension design: the suspension of drive axles is often more complex and extensive since greater dynamic forces during acceleration and braking have to be absorbed. The suspension of non-drive axles may be simpler because their main purpose is to maintain stability and even weight distribution.
• Impact on vehicle stability and handling: the drive axle is crucial for vehicle traction and dynamics, especially in difficult road conditions. The non-drive axle mainly contributes to maintaining the vehicle’s balance and stability, especially during turns and manoeuvres.

How to calculate the permissible axle load

The permissible axle load is set forth by legal regulations and depends on the axle type and vehicle structure. In Poland, for example, the regulations specify the maximum load for single non-drive and drive axles, as well as for groups of axles. These limits are set out in Article 5 of the Regulation of the Minister of Infrastructure on the technical condition of vehicles and the scope of their required equipment.

The permissible axle load cannot exceed in the case of:

• single non-drive axle – 10 tons;
• a group of axles consisting of two non-drive axles of motor vehicles, trailers and semi-trailers, with distance (d) between the component axles:

a) less than 1.00 m (d < 1.00) – 11 tons,

b) not less than 1.00 m and less than 1.30 m (1.00 ≤ d < 1.30) – 16 tons

c) not less than 1.30 m and less than 1.80 m (1.30 ≤ d < 1.80) – 18 tons

d) equal to or greater than 1.80 m (1.80 ≤ d) – 20 tons

• a group of axles consisting of three non-drive axles of motor vehicles, trailers and semi-trailers, with the distance (d) between the component axles:

a) not larger than 1.30 m (d ≤ 1.30) – 21 tons

b) greater than 1.30 m and not more than 1.40 m (1.30 < d ≤ 1.40) – 24 tons

c) greater than 1.40 m and not greater than 1.80 m or in the case of vehicles referred to in § 4 section 2, not more than 2.00 m (1.40< d ≤ 1.80 or 2.00) – 27 tons

For more detailed information, please refer to the aforementioned regulation and Art. 41, 41a and 41b of the Public Roads Act.

How does axle load affect road infrastructure?

Excessive axle load on vehicles can lead to serious damage to road infrastructure. The weight exerted by vehicles on the road surface or bridges may cause deformations, cracks or even permanent damage to the road surface. This, in turn, leads to more repairs and an increase in road maintenance costs.

Technologies and innovations in axle loads

Modern axle load-reducing technologies include advanced suspension systems that automatically adjust axle loads depending on road conditions and vehicle load. The development of air and hydraulic suspension technology significantly affects pressure distribution and improves driving comfort. Additionally, intelligent telematics systems enable real-time axle load monitoring and optimization, which helps reduce the risk of overload.

Summary: axle load matters

Axle load is a key element that affects both the durability of road infrastructure and  transport safety. Compliance with the maximum permissible axle load regulations is essential to prevent damage to roads and bridges. The development of modern technologies, such as intelligent suspension systems, allows for more effective management of this parameter, thus minimizing risks and potential repair costs.

FAQ

How to calculate axle load

To calculate the axle load of a vehicle, you need to know the total weight of the vehicle and how that weight is distributed among the individual axles. This information is often found on the vehicle’s data plate.

What happens if the permissible axle load is exceeded?

Exceeding the permissible axle load may lead to faster wear and tear of the road infrastructure and result in financial penalties of up to PLN 10,000.