4.1.23. Damages of tires because of mistakes when mounting (assembly damages)

The core of a board exploded at a tire rating

Fig. 4.26. The scheme of installation of the tire on a disk: 1 – хамп (double хамп H 2); 2 – onboard zakraina of a rim; 3 – internal shoulder of a rim (e.g. conic shelf); 4 – rim; 5 – disk; 6 – cavity; 7 – external shoulder of a rim (e.g. conic shelf)

Modern radial tires for cars are mounted only on safe disks. Their rims have on shoulders an eminence 1 on all circle (fig. 4.26).
Hamp protects the tire when driving with the low pressure of air in it from sliding from a rim shoulder.
At a rating of the tire can happen that the tire board not completely will move through an external hamp of a rim.
In this case there is a danger of an excessive extension of the core of a board with too high pressure therefore its steel threads will become torn partially or completely. The rupture of the core of a board is imperceptible outside.

Tires with the damaged board core leaky sit on a disk rim. Such tires are extremely unsafe at operation.
Besides, there is a danger that the torn board core in the movement will explode completely, and the tire will suddenly explode. At a rupture of the core of a board at a tire rating the framework also collapses.

The tire with the broken-off core of a board and the destroyed framework

Fig. 4.27. The tire with the broken-off core

In the figure 4.27 the tire with the broken-off core and the destroyed framework as a result of excessive stretching at installation is represented.
Damages of a board because of wrong or wrong mounting at the tire stand
The following mistakes when mounting can lead to serious damages of tires:
– if at roll-in of the top board at the tire stand the opposite board of the tire not completely lies in a cavity;
– if the assembly head was incorrectly adjusted;
– if the edge of an assembly roller slides on an onboard roller;
– in the presence of worn-out or sharp guides of rollers.

Tires with a board cut

Fig. 4.28. Tires with a board cut

In such cases the board which is under high voltage can be made an incision, cut and/or jammed to a wire of the core (fig. 4.28).
Often in a zone of damage traces of the beginning and end of contact with the directing roller are visible.

Essentially both boards of the tire and shoulders of a rim need to be greased with tire paste.
If damages at installation remain unnoticed, there is a danger of destruction of the tire at its further operation.
Never mount the tire without tire paste.
Do not pump up an explosive rating over 3 bars.
Do not pump up the tire over 4 bars.
At the end of mounting lower air pressure in the tire to the ordered value.