Tire maintenance & safety

Tire workload: What it is & how it's measured

Last updated 10/17/2022 - Originally published 9/24/2020
Written by SimpleTire

Heavy machinery like an earth mover or a dump truck requires tires that can safely haul a lot of weight. Engineers developed a formula to make sure these tires can work safely and effectively from project to project. For heavy vehicles, the formula is called the workload. The formula lets engineers keep track of how well the tires work for heavy applications.

These heavy-duty work tires are often immense and capable of implementation on very large vehicles like a standard 18-wheel transport truck. The workload is measured on these tires to ensure that they are able to endure the amount of stress put on them from the incredible vehicle weight and the load weight added during a working process.

What Does Workload Measure?

In the United States, workload measures ton-miles per hour (TMPH). Workload may also be called the TMPH requirement or the ton-miles per hour formula. In countries that use the metric system of measurement, workload is measured in ton-kilometers per hour (TKPH). In either case, the process of determining workload is an effort offered to prolong the life of the expensive specialty tires that are used on these immense machines. Measuring workload also keeps the people behind the wheels of these vehicles safe. People who plan to use these heavy machines should always calculate workload before starting a project to make sure they have the appropriate tires.

The formula is calculated by the average workload in tons, vehicle transport speed, and the total amount of hours used in a standard workday. By arranging the variables, an impressive workload can still be achieved without sacrificing the life of the tires prematurely. These tires become worn and stressed because of the heat they build during travel and hauling. Calculating workload enables drivers and earthmover operators to reduce the stress put on the tires, preventing premature tire failure.

Other variables are taken into account when considering workload, including the tread patterns, tire size, tire compound, and tire construction method. Some tires are more capable than others. With recent developments in the recycling of such tires, new opportunities have begun to grow in the area of industrial tire manufacturing. However, these are still considered specialty items reliant on workload calculations in order to remain in service for long periods of time. Multiple issues with tires on these vehicles can become a significant project hang-up. There are times when vehicles simply have to sit unused until additional tires can be located and worked into the budget. There is also the matter of transporting the vehicles and tires to sites capable of offering maintenance on these huge trucks, tractors, and machines.

Workload Is Not Load Range or Load Index

Engineers assign limits to the amount of weight passenger tires and light-truck tires can carry. Passenger tires have a load index, while light-truck tires have a load range. These designations tell you whether a pneumatic tire is durable enough for a certain vehicle.

Vehicles with inflatable tires are geared toward traction and maneuverability. Vehicles that use a workload formula are not equipped with these types of tires. Some of these vehicles may possess solid tires. Ultimately, these vehicles need to support as much additional weight as their load bucket or dumping bed may contain. Workload is an essential aspect of maintaining these tires.

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