Tire Ply Ratings Explained
At one time, you could gauge a tire’s construction and load-carrying capabilities by the number of plies or layers used to make the tire. The days of counting the number of plies may be gone, but the idea lives on in the Tire Ply Rating. Here’s what those ratings mean and how to get the right tires for your needs.
What Is a Tire Ply?
In the early and mid part of the 20th century, cotton fibers were used in tires to add strength. Those fibers ran at a specific angle to the tread to make bias-ply and radial tires. Steel wires would eventually replace the cotton. However, the number of plies (or layers) in a tire was still counted and used to determine its load-carrying capacity when fully inflated.
Fast forward to today, and tire plies are manufactured with rubberized textile cords wrapped under the beads of the tire. This design makes it possible to use fewer plies and layers to achieve equal or greater strength. That’s why we use the term Ply Rating. This information can also be indicated as Load Range.
Where to Find Tire Ply Information
You’ll find the information about a tire’s Ply Rating on the tire’s sidewall. You’re looking for the Construction Type or Load Range (D in the image below).
While Load Range and Ply are used interchangeably, you’ll need the chart in our article Using Load Index and Load Range to Pick the Right Tires to pinpoint the ply rating that corresponds to a Load Range of A – F.
|LOAD RANGE||PLY RATING|
When referring to the first chart in the article, you’ll notice the Load Index. This number correlates to the maximum safe carrying capacity of the tire when it’s inflated to its maximum pressure. Higher load index ratings mean your tires may be able to handle a heavier load.
If you don’t see a Load Range or Ply Rating, you might find the letters P (passenger rated, which is 4-ply rated or lower), LT (light truck, which is 6-ply rated or higher), or XL (extra load is typically 4-ply rated with a higher-than-standard Load Index) stamped on the tires.
If you drive a cargo van (such as a Ford Transit), you may see the letter C, which on these particular tires stands for “cargo” at the end of your tire size. This is not to be confused with a 6-ply rated tire. Refer to the Load Index for your vehicle to ensure you get the proper tires. If you’re not sure, stop by Les Schwab.
Les Schwab Understands Tire Ply Ratings and Load Index
You can always leave the Tire Ply Ratings, Load Indexes and Load Ranges to the pros at Les Schwab. We’ll show you the best tires for your vehicle and needs. Schedule an appointment that works for you or stop by your local Les Schwab and we’ll help you out.