Pirelli hints at new hard tyre performance, testing at Hockenheim
While Pirelli will bring its P Zero White medium compound and P Zero Yellow soft compounds to the German Grand Prix at Hockenheim on 20-22 July, much of the Formula One teams’ focus on the first practice day will be on the new specification P Zero Silver hard tyre that will make its debut following a washed-out session at Silverstone. Teams will have two sets of the new tyre on top of their usual allocation of 11 sets of the race’s nominated tyres. Pirelli’s test driver Lucas di Grassi anticipates that the tyre will offers “even better traction, particularly if temperatures are at the lower end of the scale.” The company’s motorsport director Paul Hembery said the tyre has been evolved from the current hard tyre to provide a “slightly wider” range of operating temperatures.
Hembery continues: “After a wet Silverstone, we hope to give the drivers the chance to run on the experimental hard compound tyre during free practice at Hockenheim. But the weather in Germany at this time of year can be almost as unpredictable as it is in England: when we were at Hockenheim for the GP3 Series two years ago we saw plenty of rain, although it’s been very hot in the past too.
“The new hard tyre is not a big evolution, but it has a slightly wider working range, which should make it easier for the teams to get the tyres up to temperature and maintain them in the correct operating window. We’re running them in Friday free practice only as with the championship so finely balanced, we feel that it would be unfair to suddenly alter one of the fundamental parameters that the teams have made a lot of effort to understand and get the most out of. But we enjoy a very productive dialogue with them, and we will always take into account the wishes of the majority. It’s certainly going to be interesting hearing what they have to say about the new tyre, and seeing if their impressions match up to the conclusions that we have drawn from our private testing.”
Di Grassi also stated: “It’s going to be interesting to see what people think of the experimental hard tyre, which I helped to develop. Unfortunately we won’t be able to compare it to the current hard as this is not nominated for Germany, but I think the drivers will like it: it offers even better traction, particularly if temperatures are at the lower end of the scale.”
P Zero F1 tyres’ first visit to Hockenheim
Hockenheim – which alternates with the Nürburgring to host the German Grand Prix – is one of just three new circuits for Pirelli this year, together with Bahrain and the United States. The Italian tyre firm does have some experience of racing there through the GP3 Series, which it has supplied since 2010, but no P Zero Formula One tyre has ever yet turned a wheel at the track. However, computer simulations of the circuit and mathematical modelling techniques mean that Pirelli’s engineers are well prepared for what they will face over the weekend.
Hockenheim was one of the fastest circuits in the world, but has more recently added to some long straights a much slower and more technically complex stadium section. This requires a very versatile set-up, and the tyres too have to cope with an extremely wide range of speeds and conditions. Getting good traction out of all the slow to medium speed corners is key to a quick lap, and the tyres play a vital role in this. There are also a number of heavy braking areas, with the tyres having to absorb up to 5g of deceleration forces.
Hembery says: “Coming to a circuit that is new to us always holds a different challenge, as we don’t have any of our own previous data to compare it with. But the progress that has been made with simulation is incredible: these days you can learn so much about how a tyre will behave on a circuit without even going there. These advanced modelling techniques illustrate just one example of how our Formula One involvement can help to improve our everyday road car product.”
Nico Rosberg of Mercedes, who is “very much looking forward” to a “second home race” is a fan of the track: “I think our car should suit it very well. This circuit demands a lot of downforce, which works the rear tyres a lot: particularly when it is hot.
“Hockenheim is a special track for me because when I was a little boy and my father won the DTM race here I sat next to him on the roof of the car, waving to the crowd. That was probably the moment when I first thought that I wanted to do something similar when I grew up. The atmosphere in the Mercedes grandstand and the stadium section is always something very special. I won many races here in the lower categories, and that’s another reason why I have a lot of happy memories of Hockenheim. So it would be fantastic to celebrate a great result here together with our fans in the Mercedes grandstand. We will give our all to make it happen.”
Pirelli’s test driver also has memories of the circuit, though not necessarily of the positive kind: “My personal memories of Hockenheim are both good and bad: I had the biggest accident of my career here in Formula 3 in 2005 when I touched wheels with another car and went flying upside down over the fence – but I was also twice on the podium in GP2.
“Unlike the old Hockenheim, the modern circuit is a track that doesn’t have any particular one feature that will push the tyres hard but instead the challenge comes from a combination of factors: there are some heavy braking areas, with lots of energy going through the tyre, and the stadium section relies heavily on lateral grip. You could see some understeer here if the tyres start to wear, but the main limiting factor will be traction – which is very important. A lot depends on the temperature of course and in Hockenheim anything is possible.”
Technically speaking, Pirelli notes that finding the right set-up that balances both tyre performance and durability is crucial, since high temperatures make the rears especially prone to degradation because of the constant traction demands and relatively high levels of rear downforce.
Meanwhile at Turn Six, the cars decelerate from 325km/h to 65 km/h in just 2.5 seconds, with most of the energy going through the front tyres that have to brake and turn in at the same time. The weight transfer of this heavy braking causes the rear of the car to feel loose, accentuating the natural bumpiness of the circuit.
The cars run medium to low downforce in order to get the best top speed on the straights: the aerodynamic set-up is not hugely different to Canada. But this can give a lack of grip in the slow and twisty sections. If the car slides too much, this increases tyre wear by creating more friction against the track surface.