Tire Ply Rating 18PR: Meaning & Performance Impact

Many drivers are curious about what the "18PR" printed on the side of truck and bus tires means? How will this string of numbers affect the use of tires? Today, Tire Business will explain the true face of this "mysterious number" to everyone.

In fact, this "mysterious number" is not mysterious. It represents the number of plies of the load-bearing tire. Let's first look at a set of data 11.00R20 18PR. In this set of specifications, 11.00 represents the section width of the tire, R is a radial tire, 20 is the diameter of the wheel hub, and this 18PR represents the ply level of the tire.

The tire ply level is a specific strength mark that the tire can withstand the maximum load under actual use conditions. It does not necessarily represent the actual number of layers of the fabric. In fact, in addition to marking the tire specifications and dimensions, the tire ply level must also be listed on the sidewall of the load-bearing tire.

This is because it is an important indicator of tire strength and has a huge impact on the performance of the tire.
Does 18PR mean that there are 18 layers of cord in the tire? No. The nominal number of cords in the rubber layer of the tire is not completely consistent with the actual number of cords.

The number of plies refers to the tire with high-strength material cords, and its load performance is equivalent to the number of plies of tires with cotton cords.

The ply level of the tire represents the strength of the tire to a certain extent. This is mainly because cotton cords were first used to make carcass cords, and the international practice thereafter used cotton cord layers as the basis for indicating the number of tire plies.

Tires of different plies have different load capacities. 1 ply represents the strength of 1 layer of cotton cords, and 18 ply represents the strength of 18 layers of cotton cords. When we buy and sell tires, we often find that even tires of the same specifications have different load capacities due to different ply levels.

Therefore, we need to pay attention to the numbers before the two letters "PR" when providing tires to customers, because tires of different plies cannot be used on the same axle. Tires with different plies have different corresponding air pressure standards. If they are forcibly mixed together, the inflation pressure is inconsistent, the deformation of the tire is also different, and it is easy to be dangerous when driving under high load and high speed.

The same tire has different load capacities due to different plies. Not only that, the same tire with different plies has different load indexes and standard air pressures. Of course, the prices are also different. What is the difference between 16 layers and 18 layers? The difference lies in the above aspects. Generally, the fewer plies a tire has, the cheaper it will be.

Is the higher the ply level of the tire, the better? The answer is definitely no. Although the higher the ply level of the tire, the higher the strength of the tire and the stronger its heavy load resistance, it is not suitable for all cars and car needs.

Excessive pursuit of plies will be counterproductive. As an important component of a car, tires contain too much knowledge that we need to understand and learn. Different specifications often mean huge differences in tire performance.

In the future, tire business will continue to provide you with various knowledge about tires so that you can help you recommend suitable tires to car owners and promote business transactions.