Modern car tyres are complex composites, made from up to 30 different materials, primarily various types of rubber, along with reinforcements, additives, and metal components.
Here's a breakdown of the main components:
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Rubber (Natural and Synthetic): This forms the bulk of the tyre.
- Natural Rubber: Provides good elasticity and grip. It is sourced from rubber trees.
- Synthetic Rubber: Offers improved wear resistance, durability, and resistance to heat and chemicals. Common types include styrene-butadiene rubber (SBR) and butadiene rubber (BR). Different ratios and types of synthetic rubber are used for different parts of the tyre.
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Reinforcing Fillers: These materials enhance the strength, stiffness, and wear resistance of the rubber compound.
- Carbon Black: A key ingredient for reinforcing rubber. It significantly improves tear strength, abrasion resistance, and UV protection.
- Silica: Used in conjunction with silane coupling agents, silica enhances wet grip and reduces rolling resistance, leading to improved fuel efficiency.
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Textile Cords: These cords provide structural integrity and strength to the tyre carcass.
- Polyester: Offers good strength, heat resistance, and dimensional stability.
- Nylon: Provides high strength and good resistance to fatigue.
- Rayon: Less common today, but historically used in tyre construction.
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Steel Belts: Layers of steel cords are placed between the textile carcass and the tread to enhance strength, stability, and puncture resistance. These belts improve handling and reduce tread wear.
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Chemical Additives: Various chemicals are added to the rubber compound to improve its properties and processing characteristics.
- Antioxidants and Antiozonants: Protect the rubber from degradation caused by oxygen, ozone, and heat.
- Accelerators: Speed up the vulcanization process (curing of the rubber).
- Vulcanizing Agents (e.g., Sulfur): Crosslink the rubber molecules, creating a strong and durable network.
- Resins: Improve grip and handling characteristics.
- Oils: Act as plasticizers, improving the flexibility and processability of the rubber compound.
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Bead Wire: High-strength steel wires encased in rubber that form the inner edge of the tyre. They ensure a tight fit between the tyre and the wheel rim.
In summary, a modern car tyre is a complex assembly of natural and synthetic rubbers, reinforcing fillers, textile cords, steel belts, chemical additives, and bead wire, all carefully engineered to provide optimal performance, safety, and durability.
