Tire maintenance & safety
As sturdy as a quality tire may seem, it does have its limitations. These limits are based on a series of tests carried out by tire manufacturers and are overseen by the United States Department of Transportation in order to ensure vehicle safety. Outside the U.S., there are other governing bodies that oversee tire load limits.
A tire's load limit can be found in the code on the tire's sidewall. The maximum load is also listed on the sidewall. However, this is not the recommended load. It is the absolute maximum weight the tires can handle at the air pressure recommended for that vehicle.
Load Limits and Indexes on Tires
One of the specifications listed within the tire code is that of a load index. Ultimately, these are the load limits that tires can bear. The load limit is equivalent to total weight the vehicle can safely carry. This carefully calculated limit is based on several factors including the size and type of tire.
To find the load limit, look for the tire code on the sidewall of the tire. It looks something like this: P215/60R 16 94H. In this example, the 94 represents the load limit, or the load index rating. This part of the code comes just before the speed rating.
All tires for sale in the U.S., excluding tires with a Z speed rating, are required to have this code printed on the sidewall. The tire listed in the example would be something you might find on a passenger vehicle, such as a sedan or wagon. The higher the load index rating, the higher the load limit capability of the vehicle.
The Importance of Load Limits on Tires
Load limits are determined so that tires can remain flexible, handle the vehicle's cargo, and perform a multitude of tasks if necessary. Load limits are appropriately based on the tire type, which is most often needed for the vehicle. That makes sense considering that certain vehicles are used for heavy-duty tasks, while others shouldn't be used for heavy hauling, towing, or even carrying more passengers than recommended.
An excellent rule of thumb is to travel with no more passengers in a vehicle than there are safety restraints offered for passenger safety. Loading too many passengers or too much cargo in a vehicle can exceed the tires' load limit and put your safety in serious risk, especially if the vehicle isn't intended for heavy loads.
What Can Happen to Tires Used in Excess of Load Limits?
Consider a pick-up truck that's commonly used for work-related tasks such as hauling, transporting goods, equipment, and 2-3 passengers. If this vehicle is fitted with tires intended for use on a passenger car, these tires will compromise the performance of the truck's suspension, steering response, and level of comfort. Additionally, using a low load index on a heavier vehicle that is loaded with additional weight can result in a blowout or severe tire damage.
A blowout can result in an accident with severe consequences, particularly if you're traveling at highway speeds. To avoid such problems, vehicles come with recommended tire specifications precisely tuned for that particular vehicle make and model. Use those specifications to your advantage. Your ride will be safer, more comfortable, and all-around better quality. To meet those specifications with a new set of tires, have the following information on hand while you shop: your vehicle's year, make and model, and the tire code from your current set of tires.
Is it Necessary to Increase Load Limits on Tires?
For vehicles that are consistently used to transport heavy loads, it's a smart idea to upgrade to a new set of tires that has a sufficient load rating. If your tires aren't ready for the added weight of heavy cargo, you'll quickly notice that the vehicle doesn't handle as well. This is especially true for passenger vehicles or compact vehicles.
For questions about maximizing load index ratings and total load limits, contact your local auto dealership. They have the latest information about your make and model.
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