Which Fibre Is Used to Make Tyre Cords? A Complete Guide to Materials, Performance, Industry Trends

Ever wondered what keeps a tyre from tearing apart at 120 km/h? It's not just rubber — it's the hidden fibres inside the tyre cord. These fibres give tyres their strength, flexibility, and heat resistance. But not all fibres perform the same, and choosing the right one matters. In this post, you'll learn which fibres are used in tyre cords, how they compare in strength, cost, and durability, and how manufacturers decide what's best for each tyre type.

Overview: Four Common Tyre Cord Fibres Explained

What Is Tyre Cord Fabric, and Why Does Fibre Matter?

Tyre cord fabric might look simple, but it’s critical to every tyre's strength. It’s a woven or warp-knitted material made from industrial fibres. These fibres are embedded in the tyre's carcass. They form the internal skeleton that supports weight, maintains shape, and absorbs shock. Rubber gives grip. But the fibre cords are what hold it all together under pressure, heat, and speed.

Four Key Fibre Types Used in Tyre Cords

Let’s break down the four most commonly used fibres in modern tyre cord fabric:

• Polyester (PET): Polyester is the most widely used fibre in the tyre cord industry. It has moderate strength, high heat resistance, and a low cost. It doesn’t absorb moisture like nylon does, which means it keeps its shape better. Most passenger car tyres use PET-based cords. Newer variants like HMLS polyester offer even better performance in high-speed driving.

• Nylon (PA6/PA66): Nylon brings high toughness and flexibility. It stretches under stress but bounces back—great for heavy loads and impact. But nylon has a downside: it absorbs moisture. That can lead to dimensional changes over time, especially in wet or humid conditions. You’ll find nylon cords in truck, bus, and off-road vehicle tyres.

• Rayon: Rayon offers precision. It’s made from regenerated cellulose, giving it great thermal and dimensional stability. This fibre doesn’t stretch much, so the tyre keeps its shape at high speeds or under braking. It’s more expensive and harder to process than polyester or nylon, but it’s used in aircraft tyres, high-speed passenger cars, and premium tyres.

• Aramid: Aramid is a high-performance synthetic fibre. Think lightweight armor for your tyre. It has exceptional strength-to-weight ratio, excellent heat resistance, and near-zero stretch. Aramid cords are used in racing tyres, military applications, and run-flat tyres. But it’s pricey. So most manufacturers only use it where top-tier performance is essential.

1. Technical Understanding – What Are the Most Common Fibres and How Do They Perform?

Tyre cords take a beating. They handle impact, heat, and weight—all at once. So, what makes one fibre better than another? It comes down to three key things: breaking strength, elongation, and adhesion.

Breaking Strength: How Much Load Can the Fibre Take?

Breaking strength tells us how strong a single fibre really is. It's measured in newtons (N/end), and it shows how much force it can take before snapping. A higher number means stronger fibre. Simple as that.

For example, the 840D/1 tyre cord can handle up to 69 N before breaking. This is sufficient for most passenger cars. However, for trucks or heavy equipment, where the load is much greater, you would need something stronger like the 1260D/1 or 1870D/1. The 1260D/1 has a top-grade breaking strength of 110 N/end, making it suitable for high-load applications, while the 1870D/1, with a breaking strength of 170 N/end, is ideal for trucks, buses, and off-road tyres.

Elongation Under Load: How Flexible Is the Fibre?

Stretch is good—until it’s too much. We test how much the fibre stretches under pressure, like at 17N, 22N, 33N, or 44N loads. Too stretchy, and the tyre shape warps. Too stiff, and it cracks under shock.

For instance, at a load of 17N, the 840D/1 fibre extends by 7.5 ± 1.0%, while the 1260D/1 fibre extends by 7.0 ± 1.0%. As the load increases to 22.2N, the 840D/1 fibre stretches by 9.5 ± 1.0%, and the 1260D/1 fibre by 9.0 ± 1.0%. At a higher load of 44N, the 840D/1 fibre extends by 12.5 ± 1.5%, and the 1260D/1 fibre by 11.8 ± 1.5%. This data helps us understand how fibres behave in real-world conditions, such as bumping over potholes or braking hard.

Adhesion: Can the Fibre Bond to Rubber?

A great fibre still fails if it can't stick to rubber. Adhesion is how well fibre holds onto rubber during curing and use. Too low, and delamination happens. That’s dangerous. The stronger the bond, the longer the tyre lasts.

For example, the 840D/1 tyre cord has an adhesion of 54 N/end, which is considered top-quality. The 1260D/1 tyre cord has an adhesion of 70 N/end, and the 1870D/1 tyre cord has an adhesion of 90 N/end. These high adhesion values ensure that the fibres remain bonded to the rubber, preventing delamination and extending the tyre's lifespan.

Why Different Tyres Need Different Fibres

No one fibre fits all. Tyres vary, and so do the loads they carry. For instance, PET (Polyester) is used in most passenger car tyres because it’s heat-resistant and stable. Nylon is preferred for truck and bus tyres because it handles shock and overload better. Rayon is ideal for high-speed tyres due to its great heat resistance and ability to maintain its shape. Aramid is found in racing or run-flat tyres because it’s ultra-light and nearly unbreakable.

Aramid doesn’t stretch. Not even a bit. That’s why it’s used where zero deformation is non-negotiable—like in military and motorsport applications.

2. Selection Decision Support – Should You Choose Nylon or Polyester? Is Aramid Worth It?

Choosing the right fibre isn’t just about cost. It’s about matching your tyre’s job to the fibre’s real-world behavior. Let’s look at how PET, Nylon, and Aramid stack up.

PET vs Nylon: Which Works Better for Your Application?

Both PET and Nylon are strong and widely used in the tyre industry, but they behave very differently under stress. Polyester (PET) is dimensionally stable. It resists heat and doesn’t stretch much, even at high speeds. This makes PET an excellent choice for tyres that need to maintain their shape and stability under continuous high temperatures, such as those used in long-distance driving or high-speed applications.

On the other hand, Nylon is tougher under impact. It stretches more, which helps absorb shock, making it ideal for applications where load-handling and impact absorption are crucial, such as in buses or construction trucks. However, this stretch can become a problem if not controlled properly, as it may lead to deformation over time.

Load vs Heat Resistance: What's More Important to You?

If your tyre faces continuous high temperature—like in long-distance driving or high-speed use—PET performs better. Its thermal shrinkage is low, even after hours on the road. For example, PET-based cords like the 840D/1 have a breaking strength of 69 N/end and an extension of 12.5 ± 1.5% at 44N, making them suitable for maintaining tyre integrity under high-temperature conditions.

If you need load-handling or impact absorption—like in buses or construction trucks—Nylon gives you more buffer. Nylon cords, such as the 1260D/1, have a higher breaking strength of 110 N/end and an extension of 14.2 ± 1.2% at 44N. This additional stretch allows Nylon to absorb more shock, making it ideal for heavy-duty applications where impact resistance is critical.

Fatigue vs Dimensional Stability: Which Do You Need?

Nylon’s flexibility gives it an edge in cyclical loading—think bouncing, braking, and potholes. However, this flexibility comes at the cost of shape retention. PET holds its structure better and is less prone to deformation over time, especially when bonded with rubber. This makes PET ideal for radial passenger tyres and highway conditions, where maintaining tyre shape and stability is crucial for long-term performance.

Is Aramid Worth It for Performance or Premium Tyres?

Aramid is in a league of its own. It’s ultra-strong, ultra-light, and barely stretches. Its breaking strength is off the charts; a typical 1870D/1 Aramid cord can exceed 170 N/end, with near-zero elongation. This makes Aramid the go-to choice for high-performance applications where zero deformation is non-negotiable.

Aramid is trusted in:

• Racing tyres – No deformation, even under sudden G-force

• Run-flat tyres – Keeps the tyre safe after pressure loss

• Electric vehicles – Lighter weight, better energy efficiency

However, Aramid is expensive, and most manufacturers only use it where top-tier performance is essential.

Should You Mix Fibres? Hybrid or Layered Tyre Cord Designs

Some tyres use a hybrid or layered design, combining different fibres to leverage their unique strengths. For example:

• Radial ply: PET for structure

• Cap ply: Aramid for precision

• Sidewalls: Nylon for flexibility

This hybrid design improves ride quality and lifespan by providing strength where needed and flexibility where it matters most.

Decision Matrix – Fibre vs Tyre Type vs Conditions

Use this matrix to match fibre to function—not just budget. By understanding the specific requirements of your tyre application, you can make an informed decision that balances performance, durability, and cost.

3. Cost and Procurement Factors – Which Fibre Is Most Readily Available? How Volatile Are the Costs?

Choosing a fibre isn’t just about performance. It’s also about how easy it is to buy, store, and process.

Global Sourcing and Manufacturing Hubs

You can find polyester (PET) just about anywhere. It’s mass-produced in China, India, Vietnam, and South Korea. This widespread production means PET is readily available and relatively easy to source globally.

Nylon has a solid global supply too, though it’s a bit more specialized. Top suppliers are in Japan, Germany, and China. While not as ubiquitous as PET, Nylon is still widely available, especially in regions with advanced textile manufacturing capabilities.

Rayon and aramid? Those are tougher. Rayon mills are concentrated in Indonesia and Europe, making it more challenging to source compared to PET and Nylon. Aramid is often controlled by a few big names like DuPont and Teijin, which limits its availability and increases its cost.

Price Trends: What Affects Each Fibre's Cost?

PET is stable. It’s produced in huge volumes, and its raw materials—like ethylene glycol—are widely available. This makes PET one of the most cost-effective fibres for tyre cords, with low volatility in pricing.

Nylon gets trickier. It relies on oil-derived materials, so prices rise fast when crude oil spikes. This dependency on oil makes Nylon’s cost more variable and susceptible to market fluctuations.

Aramid is in a league of its own. Low competition, high-tech processing, and limited capacity mean high price + long lead time. Aramid is typically reserved for high-performance applications where cost is less of a concern than performance.

Supply Chain Complexity: Rayon and Aramid

Rayon has extra steps—chemical regeneration, drying, precision control. That adds cost and makes lead times longer. The complex manufacturing process of Rayon requires specialized equipment and expertise, which limits its production capacity and increases its cost.

Aramid? Even more complex. It needs special equipment, chemical baths, high-pressure spinning. And many suppliers don’t offer small batches—only industrial-scale orders. This means tyre manufacturers often need to plan well in advance and commit to longer contracts to secure their supply of Aramid.

For tyre makers, that means longer contracts and advance planning.

Dip Pick-Up and Rubber Adhesion – What It Means for Processing Costs

Each fibre reacts differently when dipped in bonding agents. This process—called dip pick-up—adds weight and cost. The efficiency and consistency of dip pick-up are crucial for ensuring good adhesion between the fibre and rubber.

• PET and nylon: Consistent pick-up, easy to control in factories. These fibres are relatively straightforward to process, leading to lower overall costs.

• Rayon: Requires more care; fragile during dipping. The delicate nature of Rayon means it needs more attention during the dipping process, increasing both time and cost.

• Aramid: Lower dip pick-up, but harder to bond without custom surface treatments. Aramid’s unique properties require specialized treatments to ensure proper adhesion, adding to the complexity and cost of the process.

Poor dip quality leads to poor bonding. And poor bonding? That leads to delamination—and early tyre failure. Ensuring high-quality dip pick-up and adhesion is crucial for the longevity and performance of the tyre.

Frequently Asked Questions

Q: Are natural fibres used in tyre cords?

A: No, natural fibres like cotton or jute are not used in modern tyre cords. They lack the strength, durability, and thermal stability required for today’s vehicles. Industrial tyres rely on synthetic fibres like polyester, nylon, rayon, and aramid for their mechanical performance and bonding compatibility with rubber.

Q: What’s the difference between HMLS and regular polyester?

A: HMLS (High Modulus Low Shrinkage) polyester offers better heat resistance and dimensional stability than regular PET. It shrinks less during curing and high-speed operation, making it ideal for radial passenger car tyres and electric vehicle applications where tyre shape and consistency are critical.

Q: Can one tyre combine two types of fibres?

A: Yes. Many advanced tyres use hybrid structures. For example, polyester may be used in the body ply for stability, while nylon or aramid is layered above as a cap ply for strength and shock absorption. This allows manufacturers to balance performance, weight, and cost.

Q: How does fibre affect tyre fuel efficiency?

A: Lightweight, low-stretch fibres like aramid or HMLS polyester help maintain tyre shape under pressure. That reduces rolling resistance, which improves fuel efficiency. Tyres using such fibres often perform better in energy-sensitive applications like EVs and long-haul transport.

Q: Is aramid worth the high cost?

A: Aramid offers unmatched strength-to-weight ratio and thermal stability. While it’s expensive, it’s valuable in high-performance tyres—like those for racing, run-flat systems, or EVs—where weight, precision, and safety are critical.

Q: What fibre is best for off-road or heavy-load tyres?

A: Nylon is often preferred for off-road or commercial truck tyres. It offers high tensile strength and excellent fatigue resistance, making it ideal for shock absorption and rough terrain conditions.

Conclusion – The Right Fibre Depends on Your Goals

Each fibre has its unique strengths and applications. Polyester is cost-effective and heat-stable, making it an excellent choice for passenger car tyres and other applications where heat resistance and affordability are crucial. Nylon, on the other hand, excels in handling heavy loads and rough roads, making it ideal for truck and bus tyres where durability and impact resistance are paramount.

Rayon offers high heat resistance and maintains its shape well, even at high speeds, making it suitable for high-performance and aircraft tyres. Aramid, with its ultra-lightweight and powerful properties, is the go-to choice for racing and military tyres, despite its higher cost.

Choosing the right fibre depends on the specific requirements of your tyre type, performance needs, and budget. Engineers and buyers should carefully match fibres to real-world use to ensure optimal performance and longevity.

If you’re looking for reliable and high-quality tyre cord fabric, consider visiting the Kingdom.Kingdom Textile is a trusted supplier offering premium, industry-tested materials that meet the stringent demands of various tyre applications. Their extensive range of tyre cord fabrics includes options suitable for different types of tyres, ensuring you find the perfect match for your needs. Whether you need cost-effective solutions or high-performance materials, we provides the quality and reliability you can depend on.