Pirelli expects 2-3 pit stops in Melbourne
Pirelli is beginning its second three-year stint as Formula One’s exclusive tire supplier in Melbourne, Australia this weekend, having deemed its new P Zero White medium and P Zero Yellow soft compounds the best suited to the street circuit. Slightly harder and more durable than their equivalents last year, Pirelli believes the tires will offer decreased degradation, having supplied the new tires to three winter tests in Spain and Bahrain, but conservatively predicts that most cars will stop two-to-three times. The new regulations in F1 for 2014 suggest that there could be some surprises, especially given Red Bull’s struggles. Paul Hembery, Pirelli motorsport director, explained that its predictions are therefore tentative before the racing begins.
"This is the most radical rules shake-up of the modern Formula One era,” Hembery said, “so we’ve had to create a completely different set of tires for the brand new dynamics presented by the 2014 cars. Pre-season testing has shown just what a big challenge these new rules are for everybody, but we have worked very hard throughout last year and the winter to come up with an entirely fresh range of tires specifically designed for these latest-generation cars, featuring new compounds and constructions that actually cut down on degradation while maintaining the same level of performance. As a result, we’re still expecting between two to three pit stops per car in Melbourne, although we’ll be able to make some more exact predictions after we see the cars run in free practice. The first race of the season is always unpredictable but this will be the case more than ever in 2014."
Jean Alesi, Pirelli technical commentator added: “I’ve always liked Albert Park: for a driver it has some elements of a street circuit like Monaco and also some elements of a more traditional circuit such as Barcelona. But this year Melbourne will be even more challenging. With the return of turbos, Formula One undergoes a radical transformation both in terms of technology and driving style. There is more torque under acceleration and out of the corners, which means that the tires have to be even more resistant to wheelspin and lateral accelerations. Drivers will have to think about all this, as well as making sure that they don’t accelerate too hard and spin the car.”
Melbourne, which has hosted the Australian Grand Prix since 1996, is low grip and generally quite slippery. This increases wheelspin, which leads to a greater degree of tire degradation.
Braking is another important element at Melbourne. There are a number of heavy braking areas where the deceleration force peaks at 5g. This can cause wheels to lock up and flat-spot the tires, which will lead to an imbalance and uneven wear.
This year, there is a new brake by wire system, which adjusts the braking pressure supplied to the rear wheels to compensate for the effect of the new energy harvesting systems. This too has a certain effect on the rear tires.
There are nine areas of full acceleration on the track, when the cars are trying to put all their power (around 760 horsepower) onto the ground. This often causes more wheelspin, and consequently degradation.
Aerodynamic downforce has been reduced this year and this also has an effect on the tires. More sliding can cause uneven wear and graining – although from what has been seen during pre-season testing, graining has been reduced and blistering has disappeared, despite this loss of downforce.
The left-rear tire is worked hardest in Melbourne, with 10 right-hand corners and six left-hand corners. The longitudinal forces on the tires are more significant than the lateral forces.
Last year, Kimi Raikkonen won the race from seventh on the grid using a two-stop strategy: starting on the supersoft tire and then completing two stints on the medium. This was decisive to his win, with the remainder of the top six all stopping three times.