Pirelli's Isola: 'Spanish GP a lottery without modified tyres'

Pirelli F1 boss Mario Isola says Sunday's Spanish Grand Prix would have likely been a blistering affair that would have impacted every driver had the Italian supplier not modified its tyres.

Pirelli's decision to change the tread depth of its rubber by 0.4mm - in consultation with the teams - was the result of blistering that occurred during pre-season testing at the freshly resurfaced Circuit de Catalunya.

The change had the desired effect as the majority of the drivers completed the race on a one-stop strategy. Sebastian Vettel was an exception among the front-runners however, the Ferrari driver suggesting that Pirelli's tyre modification likely advantaged Mercedes more than it did the Scuderia.

Looking back on Sunday's race, Isola reckoned the outcome would have been very different without the lower tread structured tyres which will also be used later this season at Paul Ricard and at Silverstone.

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"If you have a high level of blistering affecting all or most of the cars, you have a lottery not a race," Isola told Motorsport.com.

"It's not the right approach and we, as a sole supplier, have to provide the same product to everyone that is a safe product, suitable for the circuit and so on.

"I don't think that the slight modification in the tread thickness changed the balance of the performance of different cars."

Isola denied claims by Vettel that the change had made the overall compound harder.

"The compound is exactly the same and the construction is exactly the same, the difference is the thickness," said Isola.

"It is difficult to explain from the technical side because if the supersoft was excluded during the race because the general feeling was that it was too soft, the problem is a bit on the other side."

Once again, Isola denied the modified tyres were introduced to cater to Mercedes' needs, or that that German had lobbied for the modification.

"We would never do something like that," said Isola.

"We work with all the top manufacturers, more than just those in F1, so why would we give an advantage to one?

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