Analysis of Tyre Bead Problems

Analysis of Tyre Problems Ⅳ Tyre’s Bead

1. Bead Empty (Delamination between Reinforced Layer and Carcass)

Symptoms:The bulging phenomenon occurs on the tyre bead in a large area. The reinforced layer is delaminated from the carcass rubber or bead filler and the interface is smooth.

Causes: ① In the process of tyre manufacturing, water and gasoline were left among the parts. In addition, there were bubbles, dust and other impurities. 

              ② Parts are not well pressed.

Liability attribution: Manufacturing issues.

2. Bead empty (delamination between Reinforced Layer and Bead Filler)

Symptoms:The bulging phenomenon occurs on the tyre bead. The reinforced layer is delaminated from the carcass rubber or bead filler and the interface is smooth.

Causes: ① In the process of tyre manufacturing, water and gasoline were left among the parts. In addition, there were bubbles, dust and other impurities. 

              ② Parts are not well pressed.

              ③ Driving under high load at high speed, the adhesion among the components is reduced, causing delamination.

Liability attribution: Manufacturing/performance issues.

3. Bead Cracking

Symptoms:There is a big area of cracks in the circumferential direction of the tire bead (on or near the waterproof line). The crack interface is neat and the rubber endpoints of the steel wire are not loose. The rubber looks like carbonizing in severe cases.

Causes: ① Parts are not well pressed. 

              ② Driving under high load at high speed, the adhesion among the components is reduced, causing delamination.

Liability attribution:Performance issues.

4. Bead Empty (Plastic Deformation)

Symptoms:There is a part of bulging in the circumferential direction of the bead (waterproof line). After cutting, the rubber is torn.

Causes:① The tyre does not match the rim (such as using narrow rims, non-standard rims; short rim edge), the bead rubber is squeezed causing deformation and bulging.

             ② Driving under high air pressure and heavy load.

Liability attribution: Usage problems.

5. Wires Dropping out

Symptoms:The carcass steel wires are blasted at the bead, and there is no delamination among the parts, no trace of trauma, no damage to the bead, and no crushing inside the tyre.

Causes:① When the tyre is under high air pressure and high load, the stress at the bead is concentrated, and the steel wires of the carcass are pulled out, causing blasting.

             ② The tyre does not match the rim.

Liability attribution: Performance/Usage issues.

6. Deformation of the Rim Causes Empty Openings

Symptoms:There is a part of bulging in the circumferential direction of the bead (waterproof line). After cutting, the rubber is torn.

Causes:① The tyre does not match the rim (such as using narrow rims, non-standard rims; short rim edge), the bead rubber is squeezed causing deformation and bulging. 

             ② Driving under high air pressure and heavy load.

Liability attribution: Usage problems.

7. Cracks under Waterproof Line

Symptoms:At the upper part of the joint of tyre bead and rim (under the waterproof line), the crack is diagonally along the entire circumference, and the surface of the crack is not regular.

Causes:① The tyre does not match the rim (such as using narrow rims, non-standard rims; short rim edge).

             ② Driving under high air pressure and heavy load.

Liability attribution: Usage problems.

8. Rim Heating Leads to Dropping out

Symptoms:The carcass steel wires are drawn out in the bead. In the corresponding position of the

rim, the bead rubber has obvious heating and scorch marks.

Causes:① Vehicle brake pads are too tight, causing overheat  of the rim.

             ② The brake system of the vehicle fails (the brake can not reset).

             ③ The frequent braking and the failure of the vehicle’s water sprinkler cause the rim to overheat.

             ④ Partial deformation of the rim leads to wear and heat generation among tyre’s parts.

Liability attribution: Usage problems.

9. Rim Rupture Causes Wire’s Dropping out

Symptoms:The tyre bead blasted and the carcass wires were pulled out. There were obvious cut marks by rim on the bead.

Causes:① The rim is of poor quality.

             ② The rim has been usaged for a long time. The bottom of the rim is cracked, resulting in wires’ dropping out.

             ③ Bead damage happened in tyre’s assembly process. 

             ④ The clamping ring is not matched. Under high pressure and high load, the clamping ring pops out and damages the bead.

Liability attribution: Usage problems.

10. Burning Bead

Symptoms:There is obvious burning and carbonization in the bead.In severe cases, the carcass wires are drawn out.

Causes:① Vehicle brake pads are too tight, causing overheat  of the rim. 

             ② The brake system of the vehicle fails (the brake can not reset).

             ③ The frequent braking and the failure of the vehicle’s water sprinkler cause the rim to overheat.

Liability attribution: Usage problems.

11. Trauma Results in Wires’ Dropping out

Symptoms:The carcass steel wires are drawn out in the bead, and the corresponding sidewall part has obvious external force to cut the steel wires. 

Causes:① The sidewall was cut by sharp objects. The steel wires were broken, and the bead was instantly dropping out. 

             ② The vehicle’s spring plate is misaligned.

Liability attribution: Usage problems.

12. Wire’s Orderly Dropping out

Symptoms: The carcass steel wires fractured at the widest part (inner side) of the bead, with no signs of trauma, crushing or delamination.

Causes: When the tyre passes through a gully or a buffer belt under high air pressure and high load, it suffers a large impact force. The internal pressure changes and the partial stress on the bead is concentrated. So the steel wires break and burst instantly.

Liability attribution: Usage problems.

13. Bead Damage

Symptoms:The bead rubber has obvious signs of cut. In severe cases, the bead wires are exposed or broken.

Causes: ① The large edge of the rim is broken or cracked under high air pressure and high load. The tyre is cut, causing cracks.

              ② The clamping ring is not matched, or the clamping ring breaks and cuts the bead.

Liability attribution: Usage problems.

14. Bead Wear

Symptoms: At the joint of the rim and bead, rubber peeling phenomenon occurs partially or throughout the circumference. In severe cases, the steel wires of the reinforced layer are exposed.

Causes:① Driving at high load.

             ② Insufficient pressure or mismatch between air pressure and load.

             ③ The rim has been used for a long time or rim is irregular ( rim is not big enough or deformation).

Liability attribution: Usage problems.

15. Broken Bead

Symptoms:The bead toe has obvious signs of cut. In severe cases, the bead wires are exposed.

Causes:The lubricant was not applied or the movement of disassembling and assembling the tyre was aggressive. The bead was damaged by the crowbar.

Liability attribution: Usage problems.

16. Bead Broken

Symptoms: At the bead part, the bead is cut and broken. The endpoints of the wire are in cutting style, and others are in hole shrinkage style.

Causes:① The vehicle is overloaded and the rim web is broken. The bead is partially cut and broken.

             ② There are stones between the double tyres, which damage the web and causage the bead to break.

Liability attribution: Usage problems.