A bulge on a tire sidewall indicates internal structural damage. This deformation signifies a weakening of the tire’s plies, which are layers of fabric and rubber that provide strength and shape. For example, impact from a pothole can sever cords within these plies, leading to air pressure pushing the weakened area outward, creating the visible distortion.
The presence of such a deformation is a serious safety concern. The tire’s integrity is compromised, increasing the risk of a sudden and catastrophic failure, particularly at higher speeds or under heavy loads. Historically, tire imperfections have contributed to accidents; therefore, prompt identification and resolution of this issue are vital for vehicle and occupant safety.