Tech race in truck and bus tyres

Premium tyre makers are in a technology race to provide ever -increasing road performance using more sustainable materials and with a smaller carbon footprint throughout the whole value chain, from materials to tyre disposal.

There are three key areas of innovation which make it possible to produce tyres that have better road performance as well as consistency of performance from the first to last millimetre of tread wear: artificial intelligence (AI), materials science, and 3D metal printing of tread moulds. These three technologies are advancing rapidly. In fact, a tyre made today would have been close to impossible to design and manufacture even a few years ago.

AI and Supercomputing

Digital transformation is actively underway in the automotive industry. For instance, Hankook is developing new truck and bus products using a virtual tyre model. Normally, the tyre development process consists of manufacturing and testing actual tyre samples numerous times to achieve the target performance. However, product development through the virtual tyre model uses a computer program instead. This program designs a virtual tyre while predicting and verifying its performance through various physical data, past test data, and AI algorithms. This process requires only one final physical validation test, so the development cost and time can be decreased quite significantly.

The compound is the single most important element of a tyre. It is created by mixing various materials, including natural rubber, synthetic rubber, and carbon black. The development process is very complex as its properties vary depending on variables such as temperature, mixing procedure, and pressure. Hankook has developed the Virtual Compound Design (VCD), a model for predicting compound properties. When developing tyre compounds, VCD technology uses AI analysis to infer the properties of compounds and create optimal compound combinations. The latest VCD system repeatedly reflects the results of calculations through virtual simulations on a cloud platform. By utilising the accumulated data, it is expected to significantly shorten the development period, as it bypasses the process of actually having to formulate and test compounds.

Materials science

Hankook has a sustainability strategy called “E.Circle”. In terms of this strategy, the company will commit to replacing conventional petroleum-based materials with 100% sustainable materials by 2050 to reduce CO₂emissions. The company is already using about 30% sustainable materials in its latest truck and bus tyres.

Generally speaking, those sustainable raw materials are natural rubber, recovered carbon, and reclaimed rubber. Furthermore, there are plans for applying a variety of sustainable materials including bio-fillers made from recycled agricultural waste and ISCC-certified synthetic rubber made from feedstock derived from post-consumer plastics (for an explanation of ISCC-certified synthetic rubber, see the sidebar).

In Europe, the impending new Euro 7 legislation will, in addition to governing emissions, include regulations on tyre and road wear particles (TRWP) based on tyre wear rate. The spread of EV trucks and buses, meanwhile, is expected to proceed at an increasingly rapid pace. Therefore, Hankook is promoting compound development and improvement with the primary objective of improving wear performance and low rolling resistance performance.

3D Metal Printed Moulds

Thanks to advances in metal 3D printing technology, the Hankook premium tyre tread design can incorporate some advanced features that happen to be completely hidden from view. These hidden grooves and tread features strengthen the new tread block by locking together the tread sections when they are in contact with the road. This more rigid tread block means less heat and less wear. It also means lower rolling resistance and, accordingly, increased fuel efficiency and mileage performance. Furthermore, as the new tyre tread block wears, the hidden features are revealed, providing new gripping surfaces and water evacuation channels. The tyre can thus maintain grip and traction performance even when it is 70% or more worn.

It is almost impossible to realise those kinds of patterns without highly developed 3D printed tyre mould and manufacturing techniques. Hankook foresaw this in advance and so the company started studying 3D printing and ways to integrate the technology into the tyre mould industry as early as 2013. The tyre producer is now leveraging 3D printing processes to produce 3D tread features including sipes, grooves, and channels in the latest generation premium tyre ranges.

Gains of 20% over previous generation products are now possible thanks to rapid advances in these three key technologies, hence why Hankook is renewing its range of products. Today, more than 80% of sales in Europe are in tyres which were launched less than three years ago; this figure will increase thanks to the launch of latest generation products which incorporate all these technologies.