Developing a tyre for the world's most innovative touring cars

This weekend, some of the world’s most technologically innovative race cars will go to battle on the track for the first time when PURE ETCR holds its inaugural race event at Vallelunga, Italy. As a Founding Partner to the world’s first multi-brand all-electric touring car championship, Goodyear was tasked with developing a bespoke tyre for these 670 hp electric racers. But what exactly goes into designing a tyre for the most powerful touring cars in the history of motorsport?

The electric cars racing in PURE ETCR have a rear-wheel-drive layout - unusual for global level touring cars - and an electric motor producing 300 kW of continuous power and a peak of 500 kW (670 hp). The result is immense torque of up to 960 Nm, which will be displayed in flat-out ‘battles’ throughout the course of a weekend. There are no long races in PURE ETCR; just rapid fast-paced sprints to the line over the course of up to just 25 km.

To handle 500 kW of power and the instant torque delivered by an electric motor, the series’ technical team at WSC Technology asked Goodyear to produce a bespoke treaded tyre for PURE ETCR. To add to the challenge, they required a single tyre for use in all weather conditions, thus cutting down on freight costs and waste, and helping both Goodyear and PURE ETCR’s sustainability targets. Enter: the Goodyear Eagle F1 SuperSport treaded ETCR race tyre.

Meeting the brief

Bernd Seehafer, Goodyear’s technical project manager, explains the process of creating a purpose-built tyre in a short timeframe: “The WSC data sheets were the starting point. We could already see that the cars are different, as they are heavier, at around 1700 kg, and have greater torque than a petrol-powered race car. From that point of view, it was clear that we needed to design a tyre that could race in both wet and dry conditions, so we looked to the Goodyear road tyre portfolio and found the recently launched Eagle F1 SuperSport would make a strong basis for our PURE ETCR tyre.

“The tread is very similar to the Eagle F1 SuperSport tyre, but a lot of details have been adjusted to the new challenge. The same also applies for the materials used and for the tyre characteristics. The compound formulation is a mix of dry and wet tyre property characteristics used in racing but tuned for the pattern, modified to ETCR needs from its road-going ‘mother’. 

“The tricky thing was to develop a compound that has wet and dry capabilities. Usually you have one tyre for dry and one for wet. All the characteristics of the tyre, be it material, compound, pattern or the general performance, have to be considered. This sounds easy. However, a race tyre that can do everything is not that common. We needed to connect certain past findings, but so far the tyre is reaching our targets in the dry, and still has wet capabilities. The tyre has the same basic principle as the consumer pattern. However, there are significantly different and stronger stiffness levels overall versus the road-based ‘mother’ tyre, to ensure good driveability on racetracks with the heavier PURE ETCR cars. Aquaplaning/water clearance is still on a good level to ensure dry and wet usage during tyre life.”

Road-to-race, and back again

The links between road-to-race and race-to-road are fundamental to Goodyear’s motorsport philosophy and a key factor why Goodyear Racing is also the exclusive tyre supplier to championships like the FIA World Endurance Championship, WTCR - FIA World Touring Car Cup and NASCAR. The added value of PURE ETCR’s electrification means Goodyear can continue putting these learnings into consumer tyres for the latest road cars and those of the future, too. 

Xavier Gavory is PURE ETCR’s Series Director, and explains Goodyear’s relationship with championship promoter Eurosport Events as far more than simply a tyre supplier. “Nobody has the kind of sustained record of success in global motorsport that Goodyear has,” Gavory says. “Goodyear and PURE ETCR share a common philosophy regarding sustainability, and it’s very good to know that by putting its electric vehicle tyres under the kind of intense conditions that competition will create, Goodyear can accelerate its learning and incorporate the lessons learned into its range of tyres for the road.” 

The shared characteristics between Goodyear’s consumer tyre and PURE ETCR race product are key to the race tyre’s versatility. In most motorsport championships, teams are provided with different tyres for dry and wet conditions, sometimes with additional ‘intermediate’ specifications in the middle, and even sometimes a range of slick tyres for different dry conditions. Creating a race tyre that does everything is a challenge, which is why the road-to-race link was so crucial. Goodyear’s consumer portfolio includes tyres designed for different applications, but all have to perform in a wide range of conditions and environments.

“If you have one tyre that needs to do everything, it’s harder because you have to react to the different requirements,” adds Seehafer. “You only have one product you can change. The PURE ETCR Goodyear Eagle F1 SuperSport tyre is an innovative design, suited to the characteristics of these powerful electric touring cars. We’re proud this tyre shares much of its DNA and technology with the road tyre. That shows the value our motorsport learning has had on road tyre development.”

^{Quotes taken from the March/April 2021 issue of Tire Technology International magazine}