Understanding Pirelli's wider 2017 tyres and how they respond to the new generation of Formula One cars will be a "major challenge" in the early stages of the season, says McLaren technical chief Tim Goss.
Pirelli conducted an extensive 24-day test programme of its new, thicker rubber last year on 2016 mule cars provided by Mercedes, Red Bull and Ferrari. McLaren decided not to take part in the programme as it felt designing and building a mule car would have been too much of a distraction from work on its 2016 and 2017 cars.
The information from all the tests has been handed to all the teams though some, including McLaren's own Fernando Alonso, think the three teams and drivers to have sampled the prototypes will have an advantage going into the new campaign. Goss thinks the eight days of testing in Barcelona will be a steep learning curve for everyone.
"Understanding what the tyres are actually going to do has been a huge challenge," he told the McLaren website. "The 2017 tyres are slightly larger in diameter, but, more significantly, they are wider. Imagine the old 2016 rear tyre now going on the front of the car, and a similar-sized increase on the rear tyre to accommodate.
"Pirelli ran a very intensive test programme during 2016 to develop the new tyres, with the support of three teams. They got lots of mileage under their belts throughout 2016, and all that data has been provided to all the other teams. But, from all of that testing, trying to piece together what we think the tyres are going to do in terms of performance, degradation, thermal stability etc, that's still quite challenging.
"And there's a couple of reasons for that: even nowadays, it's still quite difficult to understand tyre behaviour - even if you go track-testing. Additionally, the 2016 mule cars won't behave in the same way as the 2017 cars - so what we're trying to do is identify which areas of performance are attached to the tyre and which to the mule car. That's a major challenge."
"We're pretty close to knowing what we're going to get from the tyres, but really understanding how they'll sync with the new regulations will be quite a challenge. In pre-season testing, we will learn a lot."
Testing for the new season begins on February 27 at the Circuit de Catalunya in Barcelona, Spain. The four-day test is followed by another four days beginning the following week on March 7. The season begins with the Australian Grand Prix at Melbourne on March 26.