Thirty years ago, Continental used silica for the very first time in its tread compounds for car tyres. The properties of this filler revolutionised driving safety and energy efficiency in tyres. Rolling resistance has been significantly reduced, and braking distances have since been cut by nearly 50 percent.
This breakthrough was made possible by the special surface properties of silica, which form chemical bonds with rubber polymers. During vulcanisation—the process where the tyre takes its final shape—silica, along with other components, creates a strong molecular network within the rubber. The result is a more elastic, safer tyre.
Today, silica has largely replaced carbon black in tyre treads and has become an essential component in rubber compounds for cars, vans, and two-wheeled vehicles. Additionally, its production is becoming increasingly sustainable, as Continental now utilises silica derived from rice husk ashes.
“Silica in rubber compounds was a revolution in tyre technology, enabling us to almost halve braking distances on wet road surfaces. This is still an enormous safety gain today,” says Prof. Burkhard Wies. In the mid-1990s, Wies was part of the Continental team that developed the first silica-based tyres. He now leads the Applied Research and Innovation department.
“Silica compounds are also beneficial for the environment, as they reduce rolling resistance in tyres. This leads to lower fuel consumption for combustion engines and an increased range for today’s electric vehicles,” explains Wies.
The First Silica-Based Tyres in the Mid-1990s
Silica is widely used as a filler in various industries, including construction materials like concrete and bricks. However, the crystalline silica derived from quartz sand is unsuitable for tyre manufacturing. Instead, tyre producers require technically processed “amorphous” silica.
In the early 1990s, Continental was among the first tyre manufacturers to explore the potential of silica as a filler. Early tests showed promising results, leading to breakthrough developments.
The key activation occurs during the mixing process, where silica reacts with a silane-based binding agent. Then, during vulcanisation, the rubber mixture is subjected to temperatures between 120°C and 160°C under high pressure. Special moulds give the tyre its final tread pattern and shape.
Additionally, sulphur is used to strengthen the rubber compound by creating molecular bridges between rubber chains, making the tyre both flexible and durable. The silica-silane interaction further reinforces the network structure, resulting in enhanced wet grip, abrasion resistance, and rolling efficiency.
Breakthrough Performance in 1994 Road Tests
The first road tests in 1994 demonstrated significant improvements in wet road braking and rolling resistance compared to tyres containing carbon black.
A year later, Continental launched the first production tyre featuring silica—the ContiEcoContact CP. In 1996, the company followed up with the ContiWinterContact TS 770, the first winter tyre with a silica-enhanced tread compound.
“Together with passive safety innovations like seat belts and ABS, the introduction of silica in tyres has contributed significantly to reducing road casualties,” Wies adds.
Greater Sustainability with Silica from Rice Husk Ashes
Continental’s research teams continue working towards safer, more sustainable tyres. In addition to refining tyre assembly processes, the company is also developing alternative silica sources that offer similar performance benefits while reducing environmental impact.
One major breakthrough is silica extracted from rice husk ashes, a by-product of rice farming that cannot be used as food or animal feed. The production process for rice husk silica is more energy-efficient than traditional silica derived from quartz sand.
Continental has already integrated rice husk silica into its most sustainable production tyre to date—the UltraContact NXT.
What’s your take on silica in tyres? For 30 years, silica has been changing the game—offering better grip, fuel savings, and longer tyre life. Have you noticed the difference on your caravan or tow vehicle? Share your thoughts in the comments and please share this article if you found it informing.
