The new Formula E race car has undergone remarkable changes along with increased output and improved eco-friendliness. Not only was the race car replaced, but also the race tire brand replaced. Hankook Tire & Technology(hereafter Hankook Tire) became the official supplier of Formula E tires. Thus, the Formula E 2022-23 season has a completely new starting line.

The change of tire, which has a profound effect on the race car and therefore the race result, is a very important element for racing teams and drivers, as well as for everyone who watches Formula E. With the start of the new season ahead, what should we know about the Formula E official tire? Here is an interview with researchers from the project team that developed the Formula E tire.

Interviewee:
Hankook Tire Research Institute Formula E Tire Development Project team members Min-young Yoon, Su-jin Jang, Ji-woong Choi (hereafter Yoon, Jang, Choi)

Q. Was there a supplier offer from the FIA? Or did Hankook Tire present its intention to be a supplier?

A. Choi: To be precise, there was a bidding notice as mentioned earlier. The FIA first announces regulations including clear conditions so companies understand the requirements and parameters, and then companies that can meet the demand bid. Bidding is conducted in the same way for not only tire manufacturers, but also supply manufacturers for all common parts used in the race cars, such as batteries, chass, and electric motors.
To give a more specific example,
It is the most basic thing to have outstanding performance of tires which allows participating in racing, but it is also important to have the capacity to manufacture and supply the required quantity in a timely manner. In particular, since Formula E is held all over the world, the supplier's global logistics capability is essential. In addition, the eco-friendly contribution to evaluate sustainability is of utmost importance. It is necessary to establish a plan for reducing carbon emissions, utilizing eco-friendly raw materials, and establishing an overall system for evaluating the environmental impact from tire production to recycling after disposal. Above all, the supplier must also submit what kind of synergy it can create with Formula E. It can join the full-fledged competitive bidding only when these conditions are met.

Q. When I interviewed the development team for the exclusive electric vehicle tire ‘iON,’ I was told that all of the requirements concerning a tire such as grip, durability, drainage, and quietness should be evenly high due to the characteristics of an electric car. Was this tire developed in the same direction as the EV tire as the Formula E race car is also an electric car? Is this significantly different from other race car tires?

A. Jang: In fact, there were many similarities with the development of the EV tire. There was a difference from the standard race tire though. Generally, the ability to meet speed is as important as durability when it comes to a race tire. However, the conditions presented are very specific and demanding in Formula E. Therefore, it was an important task to overcome the trade-off between tire performance and develop a tire that is as balanced as possible to achieve the so-called “magic triangle” without leaning on either side. Simply, the development was very similar to the development of the EV tire development.

Q. Unlike a standard race tire, the Formula E tire has no distinction between dry and wet surfaces. Additionally, there is a requirement that there be no tire change during the race. It sounds like a new challenge for the race tire development team, doesn't it?

A. Yoon: The goal of Formula E is sustainability. That's why there is no tire change during the race. To be precise, only two sets of tires are allowed per race from the Shakedown session to Qualifying and the final race. Therefore, it was an important condition to be able to advance through the entire race course with one set of tires. From the tire manufacturer's point of view, it was a new challenge that was completely different from developing a standard race tire.

“Formula E is a motorsport where electric vehicles compete with one another. Therefore, it is an important task for the Formula E tire to deliver the ‘magic triangle’ by overcoming the trade-off between major performance, just like in the EV tire brand ‘iON’.”

- Hankook Tire Formula E Tire Development Project Team

Q. Now let's talk seriously about the Formula E tire itself. Formula E is special in terms of the circuit. The design of the road surfaces and the nature of Tarmac (road pavement material) are all different for each host city as it is a special urban track. Presumably, this increases the difficulty in developing Formula E tires.

A. Choi: Of course, the track environment was also a challenge, but the race car itself was a bigger one. Formula E is not fundamentally about an internal combustion engine. The brakes are also regenerative, so they don't generate much heat. This means the way in which heat can increase the tire grip is extremely limited. Moreover, in total, the racecar weighs only 860 kg. There is also a limit to how we can physically create grip.

Q. To solve such a problem, it would seem a real-vehicle test would be necessary. However, it would also seem the 3rd generation race car was undisclosed at the time of tire development. Is that right?

A. Yun: Right. In addition, the second-generation race car test was also not possible under the contract. So, a Formula Two race car with similar specifications was used for testing purposes. We determined the F2 race car was appropriate. Although it was a bit heavier, it has similar output. It does have a difference in the tire profile, so this part had to be modified. What we learned during testing was that Formula E tires need to be warmed up just by moving.

Q. Standard race cars use the heat generated by braking or internal combustion engines to warm-up the tires, don't they?

A. Yoon: Right. However, as I just explained, Formula E only has an electric motor instead of an engine, with different brakes. So, we did a lot of research on how to raise the tire temperature just by creating movement. We had a lot of new experiences with this.

Q. It seems that you relied heavily on digital simulation during testing.

A. Choi: It's hard to get an exact figure, however, about 40% of our testing was through simulation which was based on data. About 60% of testing was done through track tests which were conducted to see if the results obtained here were derived in the actual driving. All the tests were conducted overseas.

Q. Formula E is centered on urban tracks. Is there a difference in the result when you do a test on a regular circuit?

A. Yoon: Above all, security is the most important, so it was fundamentally impossible to do a test in an urban circuit. Instead, we narrowed the gap by creating a course with a layout similar to an urban area on a regular circuit. For example, we closely measured and observed the response of the tires and vehicle by providing the characteristics of an urban circuit as much as possible like making the hairpin corner a little tighter and creating a Chicane (Road with S-shaped curves) although it was a general circuit.

"Becoming the official tire supplier of Formula E means that we have proven our commitment and ability to go beyond the performance of a race tire and to be environmentally friendly and sustainable. Going forward, we plan to recover all used Formula E tires and recycle them through a pyrolysis process.”

- Hankook Tire Formula E Tire Development Project Team

Q. We know that Hankook Tire's goal is to maintain or improve its tire performance, while enhancing LCA and sustainability simultaneously. Please explain what LCA means here.

A. Jang: LCA stands for ‘Life Cycle Assessment.’ Our goal is to transform the value chain of tires into a sustainable loop. We considered everything from raw material supply and demand to tire production as well as recycling as raw materials after disposal. This is the social responsibility Hankook Tire considers most important. Eco-friendliness and sustainability are also important values for the FIA. It is the most important task for us as Formula E itself is a motorsport born from such a background.