Why Pirelli is keeping faith with 'difficult' C6 F1 tyre – but admits it needs to be faster

Pirelli’s new C6 tyre has proved divisive since its much-vaunted introduction in the Emilia-Romagna Grand Prix last month, but Formula 1’s tyre supplier remains committed to the idea of having six dry-weather compounds available.

However, it did admit that some of the C6’s performance characteristics needed to change – especially the lap time improvement it gives relative to the C5, which used to be the softest tyre in the range.

“I would say that the [C6] compound was doing its job,” said Pirelli’s motorsport director, Mario Isola. “Especially in Canada we had a very good qualifying in my opinion.

“The C6 is very close to the C5 but it is different in terms of behaviour. Teams struggle to understand completely the C6. They know much better the C5 – the C5 is giving more confidence to the driver. But the performance of the C6 is slightly better. If you are able to find the peak of performance of the C6, you get an advantage. Sometimes it is difficult.”

The idea of the C6 was essentially for it to be the de facto qualifying tyre during the race weekends where it’s used, leaving teams to run the hard and medium compounds in the grand prix itself. Since these were previously the two softest tyres in the range, Pirelli envisaged this would steer teams towards two-stop strategies because last year the C5 seldom lasted long.

But Pirelli has also responded to feedback from the drivers, who felt the tyres were too sensitive, and who wanted to be able to push harder for longer rather than having to engage in prolonged phases of ‘tyre management’. In making this year’s compounds less prone to thermal degradation, it has opened the door to teams defaulting to one-stop strategies.

McLaren pit stop practice

Photo by: Steven Tee / Motorsport Images

Several races have been processional affairs as a result and, in parallel, the C6 has proved more problematic than expected. First time out, several teams found it no faster overall than the C5 because they either couldn’t access its performance peak – or that peak passed too quickly and was followed by a precipitous drop-off.

Others reported their drivers felt discombobulated by the feedback they were getting through the car as the C6s heated up and the surface began to move around too much. Hence some opted for the more familiar C5s in qualifying for Imola, and again in Montreal last weekend.

“In Canada some teams and drivers preferred to use the C5 in qualifying because they felt more comfortable with the C5,” Isola said. “But that created a different situation and also the fact that the teams came to the race with more medium and more hard.

“Because usually when they have to use only the soft in quali, that means they have to choose between having one hard [set] and two mediums, or two hard and one medium. And this is not giving them full flexibility of strategy if they want to use hard and medium in the race.

“While in Canada, thanks to the fact that some of them qualified on the medium, they brought the medium to the race. And we had different strategies.”

So, while the C6 isn’t having the effect that was anticipated, it is having some effect, and that is significant enough for Pirelli to claim it as a win. Even so, Isola confirmed that Pirelli was likely to row back on its previously announced plan to bring the C6 to Singapore.

“As usual, we will simulate and find which is the selection that is giving the highest number of strategies in a small delta of total race time,” he said.

Pierre Gasly, Alpine, Isack Hadjar, Racing Bulls

Photo by: Sam Bagnall / Motorsport Images via Getty Images

“Not sure if we are still on the idea to use it in Singapore, because Singapore sometimes can be a bit more aggressive. So let's see if we want to use it in Singapore. There is still a possibility for Vegas, where it is very cold.”

For the C6 to play a part in fulfilling Pirelli’s vision of making the difference between strategies less clear cut, and making one-stop races less attractive, it needs to be less sensitive – and, more importantly, decisively quicker over a single lap than the C5.

“What I would like for the future is a C6 with more gap to the C5,” said Isola. “So now it is around two tenths of a second, we need to have at least half a second.

“So even more aggressive with a level of degradation that is similar to what we have now to generate different strategies. For next year, we are working on a C6 with this target.”