Deciphering the “password” of tire bulge

Tires are important parts of automobiles, and tires that look simple are actually very complicated. There are many types of tires. At present, the common pneumatic tires include bias tires and radial tires. They are named according to the different forms of carcass cords.
The Kumho Tire recall has not yet subsided, and Hankook Tire, also a South Korean manufacturer, has been pushed to the forefront by many car owners. Bulging, breakage…The quality of automobile tires has once again aroused widespread concern. As a relatively frequent case of consumer complaints recently, tire bulging should be regarded as the most common phenomenon in tire damage. In this regard, some customers have raised questions: Is tire bulge related to rubber quality? Today, let’s take a look at what causes the tire bulge? How should car owners prevent it?

The ply is responsible for “rough work”

Tires are important parts of automobiles, and tires that look simple are actually very complicated. There are many types of tires. At present, the common pneumatic tires include bias tires and radial tires. They are named according to the different forms of carcass cords. Let’s take a radial tire commonly used in cars as an example to understand its structure.

Tire tread: a thick rubber layer, which is the contact interface between the tire and the ground, and also has drainage and wear resistance properties.

Tire crown belt: double-layer or three-layer reinforced belt, with vertical flexibility and extremely high lateral rigidity, providing steering force.

Sidewall: The sidewall contains and protects the carcass ply, and the function of the carcass ply is to fix the tread of the tire on the rim.

Bead: The wire bead inside it can make the tire firmly fixed on the rim, so that it can be joined together.

Inner liner: It ensures that the tire has good air tightness and maintains the correct tire pressure.

Pneumatic tires are mainly composed of rubber components and plies. Regardless of the appearance of the tires, the tires are all rubber, but the rubber in the tire carcass only plays the role of combining the components of the carcass, sealing, abrasion resistance, puncture resistance and partial cushioning. The “power” is the curtain hidden in the rubber. Cord fabric is used as a framework material in tires and is the main force-bearing component of tires. In other words, the inflation pressure and vehicle load on the tires, preventing the expansion of the inner tube after inflation, protecting the inner tube from mechanical damage, transmitting traction and braking force, and other “rough tasks”, are almost all undertaken by the cord. In this regard, the “showing up” rubber output is not great.

Radial tires are very different from bias tire cords

Different from the cross-fitting of bias tire ply cords, radial tire cords are similar in shape to meridian cords. Because they rely on warp threads to generate strong force, weft threads only serve to connect adjacent warp threads, and they will be disconnected when they are pulled lightly by hand. If the warp, weft and rubber of the cord only rely on the strong force, the radial tire will easily be disconnected from the warp when it is inflated or driven or braked. In order to cure this weak link, the material of the radial tire ply is made of steel wire, and a “belt” composed of several layers of cords is added between the tire cap rubber and the ply (the ply and the belt are all The steel wire is a full-steel tire, and the belt layer is a fiber material cord, which is a semi-steel tire, so as to ensure that the tire can withstand various forces.

The culprit of bulging tires

There are many reasons for the bulging phenomenon. Generally speaking, the occurrence of tire bulge phenomenon is mostly due to unexpected strong impact during use, which leads to serious extrusion deformation of the tire between the impact object and the rim flange. For radial tires, the sidewall is the weakest place. Without the protection of the belt, the sidewall cords will break once severe deformation occurs. At this time, the air inside the tire will escape from the break. Jack up to form a bulge. Incorrect air pressure, bad road conditions, accidental impacts and negligent driving style are the main factors that cause tire bulge. In addition, frequent jaggies on the road and tires scratching against obstacles when parking may also cause damage to the sidewall and bulge.

And if tires bulge in large quantities, it is largely due to quality problems. In the tire manufacturing process, the cord is not dried enough to be glued, or the glue itself is too high in water content. According to relevant industry regulations, the normal service life of ordinary tires is 3-5 years from the date of leaving the factory. If the bulge is not caused by special reasons such as collision within this period, then the quality of the tire may be problematic.

Tyre bulge affects driving?

So, will the tire package affect the driving? Is there any danger?

The bulge on the side of the tire not only affects the driving, but also has the risk of a tire blowout, which is a major hidden danger of vehicle driving accidents. Therefore, if there is a bulge, you must not use it again, and you must go to a regular tire shop for professional inspection and replacement immediately.

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