Charles Pic ran 14 laps on the 18 inch tires at the wheel of the current E22. With few adjustments made to accommodate the very different wheel sizes â and the lack of suspension movement provide by the tire â he was well off the normal pace. However, the point of the exercise was mainly to allow the sport's key players to judge the appearance of the new tires.
Pirelli is keen to make the switch in order to encourage road relevance, and says that it could be ready to supply the new rubber as early as 2016.
"In our view, the new tires looked stunning fitted to the Lotus," said Pirelli F1 boss Paul Hembery. "And the reaction has already been felt all over the world. These are just a prototype concept, but if the teams decided that they wanted us to proceed in this direction, we have the capability to carry on development in this area and come up with a production-ready version in a comparatively short space of time.
Comparison between 13-inch (left) and 18-inch(right) Pirelli tire
"We've heard a lot of opinions already and we look forward to canvassing other opinions in the coming weeks and months. Even though performance wasn't by any means priority here, the new tires still behaved exactly in line with our expectations, so we're clearly potentially at the beginning of a huge development curve, with the wheel and tire size rules having remained unaltered for many years."
Pirelli says that the stiffer sidewall helps retain the structural rigidity of the tire, and it's also easier to maintain a constant pressure, as there is less air inside it.
Pirelli adds: "The new tires tested today have the same width as the current 13-inch tires (245mm at the front and 325mm at the rear) but a diameter that is bigger by 30mm. The weight is approximately the same as the 13-inch tyre, because although the diameter is bigger, there is a smaller sidewall. The total weight, including the rim, is around 4 kilograms heavier."
Jules Bianchi was fastest on the second and final day of testing at Silverstone as the Ferrari-contracted driver moved over from his regular Marussia seat to replace Kimi Raikkonen, who was taking a rest after his big crash at Silverstone.
Apart from Bianchi, there were a few other changes with test drivers getting mileage at Lotus (Charles Pic), Force India (Daniel Juncadella), Sauber (Giedo van der Garde) and Caterham (Julian Leal).
The day was interrupted by several red flags, and indeed proceedings were brought to a premature conclusion when Van der Garde crashed, and it was decided that the barrier needed to be repaired.
"By the end of the day I got a really good feeling in the car," said Bianchi. "Even if at the start, it was not so easy adapting to a car that's very different to the one I race. The parameters are completely different and I spent the first runs getting used to it.
"Today we worked on race setup, trying various settings, both old and new, aimed at producing improvements in the coming races. Putting on a Ferrari race suit is always a special feeling and I hope one day I can wear it as a race driver, even if I have a lot to learn."
Daniil Kvyat was second fastest, ahead of Kevin Magnussen and Van der Garde. Lewis Hamilton lost a lot of time after an off, and was fifth fastest.
"It wasn't an easy day today," said Hamilton. "We had great weather but unfortunately had some problems at the start of the day which meant we lost some track time. The guys did a fantastic job to get the car ready again and we were able to put together a few successful runs. At the end of the day, we were going to do more important runs but the red flag came out. It could have been a lot worse as it could have been raining or we could have even done no laps, but some of the things we've tried in the car feel really positive."
Sebastian Vettel was only ninth fastest as Red Bull took its turn to devote a day to Pirelli testing: "We did all the work we could for Pirelli. It was a shame we had to change the engine but the boys did a great job and we got in a solid two hours of track time at the end. We tried a lot of tires for next year, which was interesting."
Formula 1 Silverstone test results - day two:
