Pirelli manufactures first high-performance tire with guayule rubber

High performance and innovative materials with low impact on the Environment. These are the characteristics of the new tire prototype that Pirelli recently tested at the proving grounds in Italy, Vizzola Ticino and Balocco, using a Maserati Ghibli. For the first time, the company produced an Ultra High Performance (UHP) tire that contains natural guayule rubber in its composition. Guaiúle is a bush-type plant that normally grows in arid climates, but is not suitable for human consumption, and can be grown with little water and without pesticides. Thus, it becomes a viable alternative to the traditional Rubber Tree, a typically Brazilian tree.

This innovative prototype tire has already set a new record. It took just two years between the start of the project and the first practical test on the tracks. It all started in 2013, when Pirelli signed an exclusive supply agreement for natural rubber extracted from guayule with Versalis (an Italian company belonging to the Eni oil group), for the production of tires. During this short period of time, Pirelli researchers studied the characteristics of the new raw material in the laboratory, in order to evaluate what would be the best way to use it.

The program for producing the UHP prototype was made possible thanks to a research project that Versalis carried out to develop new technologies for rubber extraction; and also due to the characteristic of the plant, typically resinous. This characteristic allowed Pirelli to obtain a material capable of meeting performance requirements, in addition to being compatible with the non-elastomeric parts that make up a tire.

The research carried out by Versalis is part of the development program for a broad technological platform, which aims to incorporate the use of guayúle throughout the industry. In its first phase, with the expansion of experimental harvesting that is currently being carried out in southern Europe and, later, expanding to various technologies aimed at extracting natural rubber for the manufacture of tires.

At the proving grounds in Italy, the tires were subjected to extreme usage simulations, including wet conditions. The results demonstrated the same performance as equivalent tires, those made with synthetic polymers from petroleum products. The choice of a Maserati to test the new tires was not by chance: it is a high-performance car, capable of providing situations that demand a lot from the tires.

Replacing petrochemical polymers with alternative and renewable raw materials is a key objective for Pirelli's research division, which has been a leader in sustainable mobility solutions for many years. Along with the development of new biopolymers like these (a key ingredient in compounds), Pirelli already produces tires that use renewable raw materials, such as silica obtained from burning rice husks. This ensures not only a constant improvement in performance, but also higher and more consistent standards of environmental sustainability, both for products and production processes.

For Sergio Lombardini, director of research & development and innovative technologies at Versalis, “guaiúle is the perfect raw material for Versalis to develop a truly integrated biorefinery. Using a technological platform that aims to fully utilize guaiúle, it will be possible to produce tires and resins that will have applications in both the automotive and civil construction industries. Furthermore, other components of this raw material could be used in the pharmaceutical and healthcare sectors. The partnership with Pirelli should only increase the chances of success of this project.”

Fabrizio Sanvito, project and technical reference manager at Pirelli, added that “the testing and control phase of our rubber tires extracted from guayúle has been more than positive. The choice of a high-performance car to carry out these tests was due to the need to place the greatest possible demands on the tires and extract the most significant results. After the success of this first phase, we will now be able to evaluate these prototype tires in winter conditions.”