Caused by improper or careless mounting procedures, such as excessive force using manual tire levers, incorrect adjustment of the tire changer's mounting arm, or insufficient use of tire mounting lubricant.
The pressure and tension from the tools cause the bead wire or the casing plies near the bead to tear. When the tire is inflated, pressurized air escapes through this tear and accumulates between the sidewall plies, causing the sidewall to bulge outward.
This type of damage shows clear evidence of external force (Mechanical Damage) occurring during the mounting process after the product was delivered. It is not caused by material or manufacturing defects from the factory; therefore, it is not covered by the warranty policy.
To prevent this damage on new tires, it is recommended to purchase and install tires at standard Pirelli 5 Stars dealers or service centers. They are equipped with modern tire changers and specialized technicians who understand high-performance tire structures. Avoid non-standard manual mounting methods.