Fatigue behavior comparison

An essential aspect of carcass cord design is understanding fatigue behavior. The graph below compares the flex fatigue data of PET HMLS, Rayon, and Twaron®. The results demonstrate that Twaron® offers fatigue performance comparable to Rayon.

Forensic analysis indicates that the twist factor of aramid cords in tire carcasses is often excessively high.

High twist factors can significantly reduce the strength of aramid cords. Reducing the twist factor maintains fatigue performance equivalent to Rayon while providing a substantially higher breaking force for Twaron®.

A recommended twist factor between 200 and 220 provides sufficient fatigue performance while significantly enhancing ply strength.