How to tell if 16/70-24 23.5x25 wheel loader tire needs to be replaced？

Several cases of tire damage 1. Excessive wear of the tire crown There are four reasons for the excessive wear of the tire crown: (1) The driving wheel is slipping. The load of the loader is too large, the relative adhesion of the tire is reduced, the driving wheel slips, and the tire crown is excessively worn. The drive wheel leaves visible carbon black marks on the driving contact surface, while leaving scratches of different lengths and depths along the circumference of the tire

1. Several situations of tire damage

1. Excessive wear of the tire crown

There are 4 reasons for excessive crown wear:

(1) The drive wheel slips. The load of the loader is too large, the relative adhesion of the tire is reduced, the driving wheel slips, and the tire crown is excessively worn. The drive wheels leave visible carbon black marks on the driving contact surface, and scratches of various lengths and depths along the circumference of the tire.

(2) Insufficient tire pressure. This will lead to an increase in the load of the loader and excessive deformation of the tire, which will not only increase the driving resistance of the loader, resulting in an increase in the temperature of the tire, but also increase the wear area of the tire when it is running, resulting in premature wear of the tire crown. Frequent steering while the loader is operating can also lead to increased wear on under-inflated tires.

(3) The tire pressure is too high. For example, the tire pressure of 16/70-24 loader tires is generally 0.3MPa. If the tire pressure is too high, the contact area between the tire and the ground will be reduced, resulting in an increase in the local wear of the tire crown (the middle part in the circumferential direction of the tire).

(4) Poor road surface smoothness. The loader has been driven on rock, sand and other material sites for a long time, and its hard edges and corners pierce the colloid on the surface of the tire crown to form wounds. For a loader used in open pit, its front axle drive tires can only be used for 1.5~2 years, while a loader used for loading mineral powder (concrete site), its tire service life can reach 4~5 years , the difference is very obvious.

2. Irregular shedding of the crown colloid

Once the colloid of the tire falls off, the abnormal wear of the tire crown will be further aggravated. The reasons for colloid shedding mainly come from two aspects. First, the road conditions are poor, frequently driving on the blasted working surface or for the leveling of rock material sites, etc., the material with slender edges and corners protruding from the road surface will pierce the tire crown colloid and form a deep wound. The slippage of the wheel will inevitably lead to the blockage of part of the colloid; the second is that the original carcass of the retreaded tire has hard injuries (such as penetration injuries, process defects, poor materials, etc.), and the wear resistance of the tire crown is poor. fall off.

3. Tire puncture

During the driving process of the loader, angular gravel, steel bars, screws, nails and other slender materials protruding from the road surface, if the angle is appropriate, can easily pierce the carcass, damage the inner tube, and cause damage to the inner and outer tubes at the same time.

4. Pinch tires

Clamping means that the inner tube is folded in the inner cavity of the outer tire.

When drivers or maintenance personnel change tires, if they choose a large-sized inner tube or insert the inner tube into the inner cavity of the outer tire, use pads (used to seal the penetrating wound of the outer tire) and other reasons, which will cause the inner tube to be inappropriately distributed in the inner cavity of the outer tire. The phenomenon of tire pinching occurs, and the inflated tire is repeatedly squeezed during the driving process, resulting in damage to the inner tube.

5. Failure to adjust or replace in time

A considerable number of loader drivers have the phenomenon that the tires are not punctured and not replaced during the use of the tires, or when the tires are scrapped and replaced, and some loader 4 tires of 29.5x25 have even different degrees of wear and tear. . Especially the front axle tires, when the loader is lifting, most of the load on the bucket and the lifting device act on the tires on both sides respectively. Due to the difference in the height of the tires, the entire lifting device cannot keep the vertical vertical On the ground, the front frame and the entire lifting device will inevitably have eccentric load wear and reduce the service life.

2. Corresponding measures after the loader tire is damaged

Based on the experience of using loader tires for many years, the author suggests that the following aspects should be done in the process of using, maintaining and repairing loader tires:

1. Use a special tire protection chain in the rock work site to reduce the damage to the outer tire from rocks and other materials.

2. The wear degree of coaxial tires should be roughly the same, that is, try to adopt the principle of simultaneous replacement. Take the 23.5x25 wheel loader tires used by ZL50 series loaders as an example. The depth of the pattern is about 5cm. Compared with the new tire, the rolling radius of the old tire after the pattern is polished is very different. When the loader runs straight, the difference in the rolling radius of the drive wheels on both sides of the coaxial shaft causes the main reducer of the drive axle to generate differential speed (otherwise the tires on both sides cannot make the loader run straight), which increases the work of the differential. burden.

3. In view of the same conditions, the wheel loader equipped with 18.00x25 tires, the wear degree of the front axle drive tires is larger than that of the rear axle drive tires, and the front axle tires can be regularly replaced with the rear axle. The front axle drive tires should be kept in good condition as far as possible, generally more than 60%.

4. In order to reduce the cost of use, the rear axle drive tires can be retreaded tires, while the front axle drive tires should be avoided.

5. Before shoveling the materials, the driver should keep the bucket close to the ground and remove the scattered materials in the working area. Especially when the loader is working on the demolition site of old buildings, it must be confirmed that there are no exposed steel bars on the working site. Wait for foreign objects above the ground to prevent accidental puncture of the tire.

6. If the tire crown has been excessively worn, such as a partially exposed line layer, the tire should be replaced in time. One is that the outer tire carcass remains relatively intact at this time and can be refurbished; the other is that the inner tube remains intact, and only the outer tire can be replaced. Once the tire is punctured if the replacement is not timely, the inner and outer tires will be scrapped at the same time, and they can only be treated as waste tires, which will outweigh the gains.

7. During the process of replacing and repairing the tire, the driver should install it correctly to ensure that the inner tube is not folded and clamped. When replacing the inner and outer tires, in order to prevent the inner and outer tires and the cushion belt from sticking to the wheel hub, an appropriate amount of talcum powder can be applied to the inner cavity of the outer tire. Before applying talcum powder, the water, sand and gravel in the inner cavity of the outer tire must be removed with a rag. Especially, if the particulate impurities such as sand and gravel are mixed between the inner and outer tubes, the inner tube will be damaged due to repeated extrusion. In addition, for the newly replaced inner tube, the locking nut connecting the bottom of the air nozzle to the inner tube is generally loose, and it should be tightened with a wrench before installation.

8. If there is a penetrating injury in the tire, in addition to the method of laying cushions in the inner cavity of the tire under emergency conditions, a repair method such as fire patching that can completely seal the penetrating wound must be used. Otherwise, the "wound" of the untreated casing will repeatedly squeeze the corresponding inner tube area, resulting in damage to the inner tube.

9. After the tire puncture of the loader, it should be replaced on the spot. Otherwise, even if it is driven for a short distance, it can cause the inner tube to be scrapped, and cause damage to the outer tire and reduce the service life.

10. The driver of the loader should regularly check whether the tire pressure meets the requirements, and adjust the tire pressure appropriately according to seasonal changes. The temperature in summer is high, and the tire pressure can be appropriately reduced. When inflating tires, you must use the air pressure gauge to confirm, avoid operating by feel.

11. The tire inventory quantity of the unit used by the loader should not be too much. Because tires belong to rubber products, with the extension of storage time, the exterior of tires is easy to oxidize and shorten the service life. The longer the storage time, the higher the degree of oxidation, and the outer surface of a tire that has been stored for a long time has a gray color. Purchasing personnel can also judge the length of tire inventory time accordingly. In addition, tires should be stored in a dark and dry environment, and high temperature conditions will also accelerate tire aging.