(1) Toes
The rigid part used to fix the outer tire on the rim and not easy to stretch is called the toe mouth, which can make the outer tire firmly fixed to the rim and resist the force that causes the outer tire to detach from the rim when the vehicle is running. In order to stabilize the shape of the toe and form a rigid transition from the bead to the sidewall, the triangle rubber used for filling has a large hardness and is not vulcanizable, so the toe is not repairable.
(2) Sidewall
The rubber covering that is attached to the side wall of the carcass and is used to prevent the carcass from mechanical damage and other external effects (such as mud, water, etc.) is called the sidewall. The difference between the sidewall and the tread is that it does not bear large stress, does not contact with the ground, and is therefore not subject to wear, and the sidewall mainly works in a flexural state, so the thickness of the sidewall can be slightly thinner. However, it has to withstand large mechanical deformations and is prone to cracking under the action of ozone. Therefore, the sidewall should have low tensile strength and excellent fatigue and ozone resistance. The sidewall is the most prone to zipper punctures. Main reasons: (1) Insufficient air pressure. The use of radial tires after the tire is installed, the standard air pressure must be guaranteed, if the air loss will cause excessive bending of the steel wire on the sidewall, the loosening of the steel wire structure, and the pressure resistance will be reduced when the air is inflated again, and the zipper puncture will occur. (2) Overload.
(3) Fetal shoulder
The shoulder is located between the crown and the sidewall and is the thickest part of the tire construction. It is also the part with the highest tire temperature in vehicle operation, which is easy to cause rubber cracking. Such wounds should be inspected and repaired in time to avoid water seepage causing rust on the internal steel wires.
(4) Fetal crown
The crown of the tyre should be in direct contact with the road surface. As a result, it has to be good for abrasion resistance, low rolling resistance and noise, and excellent heat and puncture resistance. In addition, the crown is also very loaded, especially on poor road surfaces, so it must have good elastic fatigue resistance and high aging resistance.