Tyre side

It’s black, and in rubber. During the races, it is pampered, cleaned, degummed, inflated by what we call the tireman. When you install one at the front of a TCR-type car, you fill it with 1,2 bar of compressed air or nitrogen. When you put it at the back, you fill it with 1,8 bar. More generally, it is indispensable in motorsports. It’s name? The tyre.

Contrairement à la discipline mère du motorsport, la Formule 1, où Pirelli propose neuf types de pneu, en WTCR Oscaro, Yokohama ne présente ses gommes que sous deux formes. Si celui que l’on appelle le “pneu pluie” (à gauche sur la photo) ressemble comme deux gouttes d’eau à un pneu lambda, le “pneu slick” (à droite), lui, est spécifique au sport automobile. Il présente la particularité de disposer d’une bande de roulement entièrement lisse. A l’image d’une chaussure à crampons pour un footballeur, il permet d’obtenir une plus grande surface de contact avec le sol, ce qui améliore considérablement l’adhérence, l’endurance et la vitesse de la monoplace sur une piste sèche. C’est ce que l’on appelle le grip.

Performance

Sunday May 20th 2018, in one of the garages of the Zandvoort Circuit, in the Netherlands. Yann Ehrlacher just wrapped up his second win of the season. A glass of champagne is offered to him: “Thanks, but i never drink alcohol“, answers the 21-year old. After giving the glass to one of his mechanics, he gives us a few moments to talk about tires: “A good tyre, is a new and hot tire. That’s where it’s the most efficient“. Aurélien Comte, DG Sport driver, seems to be on the same wavelength. He adds:

"A good tire, it is also one that has grip and doesn't degrade too quickly."

More or less different depending on the manufacturer, the tyre forces the driver to adapt. Between two races, we speak with Jean-Karl Vernay (Audi Sport Leopard Lukoil Team), current TCR International Series champion, where he drove on Michelin tires. Today in the WTCR Oscaro (with Yokohama tires), he explains to us: “To go from one manufacturer to another doesn’t really change your driving style. It is the way of exploiting it that is different. For example, with Yokohama, the rubber is rather soft. The tyre is at its peak of performance during the first lap, on a circuit such as Zandvoort. With Michelin you have to do two or three laps for the tyre to degrade”.

To feel and find the moment where the tyre is at its best, Comte, winner of Race 2 of the Netherlands weekend, sees only one solution “The driver can only count on his experience and his sensibility. To find performance, you need to know how to put in performance, without forcing it“.

The drivers have one question they do not need to think about during qualifying sessions because “in qualifying you can only go out on new tires“, says Yann Ehrlacher, world championship leader. “You only have one lap to be good and do the best possible lap” adds Vernay. Ehrlacher goes on:

"If you go out on a second run with old tires on a circuit like this, you will loose a second compared to your last lap. Yokohama tires are perfect for a sprint."

Strategy

Perfect for sprints indeed, but the slick tires from the Japanese brand are not ideal for endurance. One lap with maximum performance on one race is not much… Especially when we know that at Zandvoort, you have to drive roughly 15 laps before passing the checkered flag. “Starting from the fifth lap we are really obligated to concentrate to save the tires during the race“, notes the Honda driver. To remedy, each driver has his way of saving rubber despite having 28 tires per driver for a race weekend.

On the WTCR Oscaro, the cars are front-wheel drive. That means the power from the engine only goes to the front tires. By consequence, the front tires will heat a lot quicker than the rear tires. It is then, on the starting grid, after the outlaps and on the formation lap that the teams start to play their strategies.

“We all start on new tires. During two out laps (before the formation lap), we try to heat the tires without damaging them. For this we do longitudinal braking (over a distance)”, confesses Yann Ehrlacher. “I do a lot of burn (brutal acceleration)” says Comte, “It’s a good way to heat your front tires, and then depending on my feeling, i can switch my hot front tires for my cold rear tires on the starting grid. Or we just put on new tires at the front to get the most out of the performance of the rubber”. A tactic that is often seen on the WTCR Oscaro, since Audi Sport Leopard Lukoil Team uses the same strategy: “It is a way of having rear grip, all in keeping new tires up front“, says Vernay. Honda-side, and at All-Inkl.com Racing, we go for a different strategy, by not touching the tires on the starting grid. Ehrlacher says: “Today, we didn’t change. We kept the same tires between the formation lap and the end of the race“.

Which of these strategies are the most efficient, we don’t know. But one thing is certain: they all work because Yann Ehrlacher, Aurélien Comte and Jean-Karl Vernay are none other than the three winners of the Race of Netherlands 2018.

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