How to Determine Fleet Tire Load Ratings

In today’s competitive world, fleet managers need to have an in-depth understanding of their truck tires and know how they can impact the fleet’s bottom line. One aspect of fleet tires that affects tire performance is fleet tire load ratings. Let’s explore everything you need to know about them!

What Is the Load Rating of a Tire

The load rating of a tire is essentially the estimated weight a tire can carry. The load capacity of a single tire and the number of tires in a vehicle determine the overall load-carrying capacity of that vehicle’s tires. The tires you use need to safely support the weight of your vehicle and the load that it’s bound to carry. If a tire’s load rating is inadequate, it might overheat and self-destruct.

It’s why you need to ensure that the replacement tires for your vehicles have the same or better load rating than the original tires. For instance, if you have to replace an original tire of a light equipment work truck with a passenger car performance tire on an SUV, the replacement tire needs to meet or exceed the specific load requirement for your vehicle’s weight.

What Factors Affect Tire Load Rating

A tire’s load rating directly affects a fleet vehicle’s carrying capacity. With that said, load ratings influence both truck and passenger tires. All tires – big, medium-range, and small – come with a recommended load rating, which is determined by a combination of varying factors, such as tire size, application, construction, and inflation pressure.

How to Calculate Fleet Tire Load Capacity

If you want to determine the load range capacity of individual tires, divide the gross weight of your vehicle by four. For instance, if your vehicle’s gross weight is 4,500 pounds, then each tire of your vehicle should be able to support about 1,125 pounds without incurring any damage.

With that said, the gross vehicle weight does not take the additional load, such as the weight of equipment, passengers, and driver, into account. To be on the safe side, you should always select a tire that exceeds this minimum weight capability. If you select a tire that provides you with a greater load capacity, also known as reserve load capacity, your vehicle will be able to respond to and handle higher-stress emergencies when loaded to the brink.

Understanding Maximum Tire Load Range

So, how are fleet tire loads rated? A tire’s load rating or “max load” designates its maximum load-carrying capacity when inflated to the recommended pressure. A tire’s maximum load rating is molded into its sidewall. You should never exceed this limit or the maximum vehicle load limit that is typically highlighted on the vehicle tire placard.

Each tire is designed to handle a specific maximum load, and overloading your vehicle beyond that recommended load will result in a buildup of excessive heat in the tire, which might lead to tire failure or rupture.  

A tire’s load index number, which you can see on its sidewall, is an assigned number that designates that tire’s load-carrying capacity. For alphanumeric tires, the maximum load capacity is indicated with an alpha code. The letter can range from “A” to “N.” The tire with the greatest load-carrying capacity at its recommended inflation pressure has the highest letter.

The maximum inflation numbers located on a tire’s sidewall indicate the maximum load that the tire can safely carry at the maximum tire pressure without incurring any damage. A tire’s ability to endure pressure is determined by its construction. If reinforcements such as the bead, belts, liner, and carcass of a tire are stronger, it will be able to withstand greater pressure.

How to Read Fleet Tire Load Information

Typically, alphanumeric tires have a load range of B, which means that these tires have a limited maximum load capacity and can only carry the maximum inflation pressure of 32 psi. Tires with load ranges, C, D, and E, can carry greater loads. Most of the tires that fall under these ranges are used for fleet vehicles that have light-truck applications.

The load-carrying capacity of P-metric tires, commonly used in passenger cars, is rated as “Extra Load” or “Standard.” The ones with the standard load capacity have a limited maximum load capacity at the maximum inflation pressure of 35 psi. Meanwhile, tires with an extra load rating can carry a maximum load at the maximum inflation pressure of 41 psi.

Typically, a standard load tire does not have a mark designating its load capacity. On the other hand, extra load tires usually feature an “Extra Load” marking. Such tires can be identified by an “XL” imprinted on their sidewalls.

Some standard load tires might have a marking of maximum inflation pressure of 44 psi, even though their recommended inflation pressure is 35 psi. This does not mean that these tires have a special load-carrying capacity. It only indicates that the tie can handle higher inflation pressure in emergencies that demand superior performance. 

Lastly, the fleet tire load indices of light work trucks and passenger car tires typically fall anywhere between 70 and 110. The sidewall of these tires indicates their size, load rating index, and speed rating, which is the optimal speed that a tire can safely maintain without lacking in performance.

The Bottom Line

Every fleet manager needs to understand that the weight a vehicle in their fleet can safely carry ultimately depends on the maximum fleet tire load capacity. If you try to load more weight on your vehicle than the recommended load capacity of your tires, the additional load will put a burden on your tire and cause damage to them. It’s why you must read the load rating index of a tire imprinted on its sidewall before using it for your fleet vehicles. It will ensure that you don’t face any trouble with your tires while loading your vehicle and taking it to and from a job site.