Plies and Ply Ratings: Bigger, Stronger, Faster

Plies are the thicknesses of material used to build a tire—plies give strength, which is why the strength of a tire is determined by the number of plies and the material that’s used for the plies. They are anchored on each sidewall and go across go from one sidewall across where the tread will be and down the other sidewall. When tires were first invented, cotton was used for the plies, and large tire manufacturers built entire towns around their cotton plantations. Now, exotic materials like polyester and nylon used in the construction of tires.

You might think more plys are always better. But that’s not necessarily always true. The ply rating is more important. One ply may be as thick as four plies and so will get a four-ply rating. Plies increase puncture resistance, are crucial for strength, and tires with more plies or a higher ply rating will take more abuse.

But there are some negatives with more plies or a higher ply rating. The more plies or higher ply rating reduces the flexibility of the sidewall and increases the weight of the tire. You must also be aware of the higher temperature with more plies, which is due to more material.

Some tires have the ply or ply rating listed by number and others have the load rating or ply rating listed by letter. For instance:

• A = 2 ply
• B = 4 ply
• C = 6 ply
• D = 8 ply
• E = 10 ply
• F = 12 ply