The main problems with tire refurbishment are quality and safety issues. If the quality is excellent, there will be no safety hazards.
The quality issues mainly include: 1. issues with the body itself, 2. imprecise repair techniques, 3. poor quality of raw materials, and 4. unstable vulcanization temperature and pressure. These can all lead to defective refurbished tires.

1. Fetal problems
There are more than 5 fetal wounds, wounds larger than 5cm, damage to the tire opening, and damage to the ply and meridian layers, all of which cannot be refurbished. Usually, the operator determines whether a tire can be refurbished by tapping and listening. You can also choose to purchase a tire expansion detection machine and an electric spark detector to detect the tire body.

2. Inadequate repair process
The repair process mainly includes external repair, internal repair, brushing glue, and filling glue. For external repair, steel wire wheels or bowl shaped metal grinding heads should be used to polish the worn parts as much as possible without damaging the buffer layer or belt layer. When polishing, it is necessary to follow the direction of the curtain line and also polish the grooves on the shoulder of the tire that exceed 10mm, with a width of 20mm, to increase the bonding area between the tire surface and the tire body. The quality standard after small grinding is that all parts of the tire that should be filed have been filed, and the grinding pattern is uniform. The curtain line head should not exceed 1mm, and no bright residue should be left in any part, Floating glue thread and burning phenomenon. According to the size of the through hole and the number of layers of the non through hole damaged curtain line, internal repair should match patches for reinforcement. Steel wire wheels should be used to polish according to the size of the patches. Thick oil and rubber can be retained, but new filing surfaces must be polished. The actual polishing size should be 10mm more than each side of the patch. When matching patches, the center position of the patch must be aligned with the center position of the through hole or non through hole, and cannot be offset. After matching patches, the model of the patch should be indicated next to it, For the convenience of future operations, if the tire body is damaged by more than half of the curtain layer, it should be matched as a through hole, but the size can be slightly expanded. Finally, clean the inner and outer rubber of the tire body and proceed to the next process of filling the rubber.

3. Poor quality of raw materials
The quality of tread rubber directly affects the mileage of the tire. The function of the middle cushion rubber is to pull the tire surface from separating from the tire body, and commonly referred to as debonding, it is related to the middle cushion rubber. Friends who purchase tire flippers can think for themselves, spending 800 yuan to buy a 1200R-20 tire can run 50000 kilometers, and the same type of tire can run over 80000 kilometers for 1000 yuan. Did you earn an extra 200 yuan by driving 30000 kilometers with tires? If you want to buy cheap tires, the manufacturer has to use cheap materials.

4. Unstable vulcanization temperature and pressure
Many tire flipping factories may not be aware of this issue, as the equipment manufacturers they supply may not be aware of the underlying principles.
Sulfurization is a chemical reaction with a temperature of 115 degrees Celsius and an error of 1 degree Celsius. The inner tube pressure is 8 kilograms, the packaging pressure is 4 kilograms, and the vulcanization tank pressure is 6 kilograms, with an error of 0.1-0.5 kilograms. After the middle cushion rubber reaches the specified temperature and pressure, it will produce a vulcanization reaction, effectively expelling the air from the tread rubber in the middle cushion rubber using the pressure difference. On the contrary, if the temperature and pressure cannot be reached or exceeded, accurate chemical reactions cannot be carried out, and there is still air inside the tire, resulting in the phenomenon of bulges.