"Ply Rating" is used to identify a given tire with its maximum recommended load when used in a specific type of service. It is an index of tire strength and does not necessarily represent the number of cord plies in the tire.
A tire ply rating is an expression of the tire’s strength and capacity. The ply rating translates in a very direct way to tire capabilities and limitations,
especially when it comes to inflation and load capacity.
If you plan to haul, tow, or carry heavy loads with your vehicle, then understanding the ply rating of your tires is a must.
These days, tire ply rating is more commonly expressed as “load range.” The days of cotton layers or plies forming the internal construction of tires are long gone, so the ply rating no longer has a direct connection to a tire’s construction and a number of layers. Modern tire engineering and materials make it possible to create greater tire strength and capacity without adding layers.
Modern load ranges correspond to the ply ratings of old. Load range is expressed as a letter, with letters further down the alphabetic order corresponding to increased strength, with higher psi (inflation pressure) potential and heavier load capacity.
