The ABCs of Tire Load Capacity

Achieving optimal tire load capacity is a crucial balancing act that every fleet strives to master. The load on the tires directly impacts profitability, the environment and the fleet's operational efficiency. It is essential to maximize each delivery's potential while preserving tire performance, minimizing wear and prioritizing safety.

Tire load capacity is defined as the maximum weight that a tire can safely handle, but it's important to note that relying solely on the maximum PSI located on the tire's sidewall may not provide the optimal pressure for your truck's tires. Gone are the days of adhering to a standard PSI of 100, as it fails to align with the recommended tire pressure tailored to your truck's unique application requirements. Double Coin has compiled a comprehensive list of essential factors to consider when determining the correct tire inflation level. By the time you finish reading this article, you'll realize that ensuring optimal tire performance for your fleet can be as easy as ABC.

Avoid overloading, under- and over-inflation:

The first step in identifying the proper air pressure for each wheel position and ensuring safe tire operation that meets performance expectations is to determine the overall Gross Vehicle Weight (GVW) distribution for all five axles. By following the recommendations provided by the vehicle and tire manufacturers, you can maximize the tire's capacity to support the load and maintain optimal performance.

Determining GVW means taking a look at your truck's steer axle capacity.  If an 80,000 lb. vehicle has an average steer axle capacity of 12,000 lb. to 13,200 lb., this means that each tire requires a load carry capability of 6,000 lbs. to 6,600 lbs. To achieve this rating, up to 115 PSI will be needed to carry the load.

For the drive and trailer position, weight is uniformly distributed at 34,000 lbs. for each position. With each position having eight tires, the load capacity for each tire is lower, resulting in a lower air pressure requirement. Inflating tires between 90 to 95 PSI provides more than adequate load carrying capacity, while also creating the functionality for each tire to operate as intended. For today’s trucks, 100 psi on the steer axle could result in premature failure due to under-inflation/overloading. For the drive and trailer axles, 100 PSI is far too much air pressure, which will lead to shoulder wear and the increased occurrence of impact damage. However, finding the happy medium for both the steer and drive axle tire PSIs requires more than just a simple guesstimation.

Browse manufacturing resources:

When figuring out how much weight a truck can carry on the highway, there are two important resources to consider. First, there's the vehicle's placard, which provides details about the load capacity for each axle, tire size and air pressure of the power unit or trailer. Second, the tire manufacturer's load and inflation table, typically found in its respective data book, provides additional information. This comprehensive approach helps maximize safety, efficiency and compliance with regulatory requirements, ultimately contributing to a smooth and reliable operation on the highway–a win-win for all involved.

Check the casing:

The way a tire is built affects how much weight it can carry, and the design of the casing greatly impacts a tire’s load capacity in this respect. If you look at a radial truck tire, the casing is made up of layers of rubber-coated steel cords arranged in a radial pattern around each bead bundle. These cords provide the casing with its strength. To adjust the tire's load capacity, manufacturers can increase or decrease the frequency of radial body piles.

Following recommendations from vehicle and tire manufacturers plays a crucial role in maintaining an efficient and compliant fleet. Not only does proper PSI contribute to the overall commercial tire performance, but it also preserves the tire’s casing integrity, enabling the possibility of retreading—a cost-saving and sustainable option gaining more and more popularity in the industry.

By following these recommendations, you can ensure that your truck's tires operate within designated parameters and maximize their lifespan and performance, creating favorable conditions for extending tire life, retreading and minimizing the need for frequent tire maintenance and replacements.