Pirelli believes a more mature track surface and warmer temperatures compared to last year are the main reasons behind the impressive speed of Formula 1's new-spec cars.
Pre-season testing in Barcelona is seeing teams deliver lap times that are better than what most had projected given this year's new aero rules that are theoretically expected to impact performance levels.
On Monday, Sebastian Vettel's fastest lap time was more than one second faster than last year's opening day best lap.
While many have been surprised by this year's relative performance, Pirelli F1 boss Mario Isola offered two specific reasons for the better-than-expected speed of the 2019 contenders.
The Italian engineer points to the Circuit de Catalunya's track surface and to warmer temperatures to justify the quick lap times.
"If I compare the winter test last year, the race [Spanish GP] last year and the winter test this year, there is a big evolution of the tarmac," said Isola.
"The tarmac was new at the winter test last year. It was very smooth with a lot of grip coming from the bitumen on top of the tarmac.
"For the race it was slightly different with the usual evolution we can see, and now there is another step compared to the race.
"I believe the influence of the tarmac is higher, and the temperature [it was warmer this year] is playing a big effect. We know that."
Isola was also queried in Barcelona on the 'glossy' finish applied to Pirelli's range of 2019 compounds, a change of appearance linked to production changes.
"We are using new moulds that have a chrome treatment," he explained. "We tested these for the first time last year in F2.
"The reason why we introduced this technology is because the hypersoft last year and the C4/C5 [softest 2019 compounds], are very sticky and, when you vulcanise and cook the tyre, it is difficult for the mould sometime.
"You see small imperfections on the tread because of this adhesion between the compound and the moulds. With the new moulds, they are a lot better.
"They look nicer, in terms of technology it is better but the specification is the same that we used in Abu Dhabi [test] last year."
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