Load Range vs. Load Index

LOAD RANGE AND PLY RATING

Tire experts use a few different classifications to describe a tire’s ability to hold air pressure and carry weight. Load range is one of these and describes how much weight a tire can carry. It’s listed on the sidewall of your tire, represented by a letter.

This letter tire load rating gives you a comparative idea of the tire’s toughness; helping you understand how much air your tire can hold, how much weight it can carry and a relative measure of the tire’s durability. Tires with a higher load range can carry heavier loads.

It’s pretty helpful to know how to read a tire sidewall as it gives you a wealth of information about your tire.

The load range is based on an older measurement called ply rating. All tires are constructed of rubber and cord layers referred to as "plies". Historically, more plies gave a tire a larger load-carrying capacity, so manufacturers would count the plies and use this number to denote this measurement.

However, modern tire construction uses fewer, stronger plies. Therefore, load range simply defines the tire’s toughness and maximum allowable air pressure, as opposed to specific information about the actual plies being used. For example, a "C" load range indicates that a tire is equivalent to a 6-ply construction tire. This tire isn’t built with 6 plies, but rather one or two plies of equivalent strength.

The load range is indicated by a letter on your sidewall but it is also accompanied by a number to indicate the maximum air pressure the tire can take. Using the above "C" example, you may see a  "C1" or "C2". "C1" and "C2" are both 6-ply rated, but C1 has a max air pressure of 50 PSI and C2 has a max air pressure of 35 PSI. This is true for other ply ratings, too.

Tires on a sedan, coupe, crossover or minivan are usually unmarked because they have a standard 4-ply rating and do not require higher load-carrying abilities. However, you may find these tires marked as Standard Load (SL) or Extra Load (XL or Reinforced). Both have a 4-ply rating, but the Extra Load can support additional load at up to 42 PSI while the Standard Load is 36 PSI.

It’s best to have a tire expert make sure your tires are properly rated to support the weight of your vehicle.

Check our load range chart, which notes the ply rating and the max load carrying air pressure.

LOAD INDEX AND LOAD-CARRYING CAPACITY

Load index is another way to further describe a tire’s carrying capacity. The load index explicitly indicates the maximum load a tire can carry. To find your tire’s carrying capacity, look for the load index number on the sidewall. Load index is a more precise method of measurement than load range which focuses mostly on construction.

The load index number indicates a tire’s carrying capacity when inflated to maximum load-sustaining pressure. It further explains the tire load range measurement by adding more specifics to the rating.

Find your tire’s load-bearing capacity by checking our load index chart below. Most cars and light trucks have load index values ranging from 70-124.

Load Index and Carrying Capacity Table

If you have any questions about load range, load index or what tire might be the right option for you, please give us a call or stop by your local store. You can also get a shorter wait time in-store when you buy and book online!