The term "crossply" (IPA: /kɹɒs.plaɪ/) refers to a type of tire construction in which the reinforcing cords are arranged diagonally to the direction of travel. This differs from the more common radial construction, in which the cords run perpendicular to the direction of travel. The spelling of "crossply" reflects the use of the word "cross" to indicate the diagonal arrangement of the cords, along with the word "ply" to indicate the layers of material used in tire construction.
A crossply, also commonly known as bias-ply, is a type of tire construction that was widely used before the advent of radial tires. The term "crossply" is derived from the way the tire layers are positioned during manufacturing. In a crossply tire, the layers of rubberized cords, or plies, run diagonally across the tire from bead to bead, forming a crisscross pattern. This design gives the tire its strength and durability.
Crossply tires typically have a sturdy sidewall, providing good resistance against impacts and cuts. They are also less prone to damage from curbs or potholes compared to their radial counterparts. However, due to the diagonal ply arrangement, crossply tires tend to have a stiffer and less flexible sidewall, resulting in a less comfortable ride and lower overall performance.
Moreover, crossply tires have a distinctive characteristic known as "cross-ply tire squirm." This refers to the slight lateral movement experienced when cornering or maneuvering at high speeds, caused by the diagonal ply construction. Although this can affect handling and traction, crossply tires were widely used in the past due to their lower manufacturing costs and better load-carrying capacity.
With the emergence of radial tires, which have plies that run radially from bead to bead, crossply tires have become less prevalent, particularly in passenger cars. Radial tires offer improved ride comfort, better grip, and fuel efficiency. However, crossply tires are still commonly used in specific applications such as heavy-duty trucks, agricultural and industrial vehicles, where their robust construction and load-carrying capacity are valued.
The word "crossply" is derived from two separate terms: "cross" and "ply".
"Cross" refers to the way the layers of a crossply tire are arranged. In a crossply tire, the cords in the tire carcass run diagonally from bead to bead, creating a crisscross pattern.
"Ply" refers to the individual layers of the tire's construction. In a crossply tire, the individual layers or plies are arranged diagonally to each other at an angle (typically 30 to 40 degrees).
Therefore, the term "crossply" describes the specific construction method of stacking layers diagonally in a tire.