If you’ve ever shopped for tires, you may have come across these terms and wondered “What is the difference between Tire Load Index and Load Range?” You’re not alone! Many tire shoppers are wondering the same thing, and the information available can be confusing to understand. At Tire Research, we want to make sure that everything you want to know about tires is easy to find and understand. In this blog, we’ll explain what the Load Index and the Load Range of a tire refer to, and what they mean for you as a tire customer.

What is Tire Load Index?

The Tire Load Index refers to the total weight that a single tire can safely bear when properly inflated. The Load Index is indicated by a two- or three-digit number which corresponds to an actual weight, which you can find on a Tire Load Index Chart like the one seen below. For Light Trucks or vehicles with two sets of rear wheels (also known as “dually trucks”), the rear tires will have two numbers showing for the Load Index, for example: 121/118Q . The first number indicates the maximum weight that each tire could carry individually, and the second number indicates the weight that the tire could carry when it’s mounted as a dual rear wheel, paired with another of the same tire. Although this may seem confusing, the reason for the lower second number for dual rear tires is that it coincides with the weight one tire could safely bear alone if one of the two tires were to fail.

Tire Load Index Chart

What is the Tire Load Range?

How is the Tire Load Range different from the Tire Load Index? While the Load Index of a tire indicates how much weight it can bear when correctly inflated, the Load Range of a tire indicates the actual strength of the tire itself. Tire Load Range can also be referred to as Ply Rating, since in the past, tires were constructed of multiple layers, or plies, of cotton. The more plies, the stronger the tire would be. Now, tires are constructed with different materials, but still use that same measure of strength, with a letter from A to F representing a certain number of plies. For example, a tire with a Load Range Rating of C equates to the strength of a tire with 6 plies. The higher the Ply Rating, the stronger the tire and the heavier load it can carry. Sometimes the Tire Load Range is molded onto the tire sidewall as a Ply Rating, and looks like this: 10PR, which in this example shows the tire has a 10 Ply Rating, equivalent to Load Range E. If you’re wondering what Tire Load Range you’ll need for towing or hauling, you can see in the Tire Load Range letter chart below that F-Rated tires have the highest ply rating, meaning they are ideal for hauling or towing heavy vehicles and loads. Load Ranges and Ply Ratings do go higher than this, but tires with those higher ranges and ratings are used mainly by commercial vehicles.

How to Find the Load Range Rating on a Tire?

The tire’s Load Range may be difficult to find because often it is very small. It is typically molded into the sidewall of the tire close to the inner rim, and will look something like these images below. If you can’t find the Load Range printed separately on a tire, it may be indicated in the tire size. For example, tire sizes with the letter P indicate a tire that is rated 4 Ply or lower, the standard for a passenger vehicle. A tire with a standard load range rating for a passenger vehicle may also be indicated by Load Range SL, which stands for Standard Load. Tire sizes with the letters XL indicate a tire with a 4 Ply rating that is reinforced and has a higher than standard Load Index (how much weight each tire can carry). A tire with LT in the size means that the tire is meant for Light Trucks and is 6 Ply rated or higher.

Understanding Load Range and Load Index

As you can see, Tire Load Range and Tire Load Index look similar but actually represent two different but important characteristics of a tire. This blog should help you understand both, and better know what to look for when shopping for new tires for whichever vehicle you drive.

For information on related tire topics, read our previous blog, How Do Tire Sizes Work?

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