Formula One is at Hockenheim this weekend, for the tenth round of the 2008 FIA Formula One World Championship. The German venue has already been the host of 30 race weekends prior to this month’s event but this is the first time ever that the Bridestone Motorsport team will be using their grooved dry-tyres for a Formula One car.
The 4.57 kilometer long circuit features 17 corners that make it an extremely “stop-start” kind of track. Each express section is followed by a slow corner on a track where the first two sectors are significantly faster than the final sector of the stadium complex part of the track. This part has a number of slower turns that make gaining speed very difficult.
“Hockenheim is a track that is quite harsh on tyres because there are many different types of corner,” explains Hirohide Hamashima, Bridgestone Motorsport’s Director of Motorsport Tyre Development. “Particularly notable is the Turn Five Parabolika curve which is a very long, high-speed left hander. Because of the length of this corner, and the high speeds through it, there are a lot of lateral forces going through the tyres which generates a lot of heat.”
Along with the tyre-beating Turn Five, there are two long straights where the cars can easily top 300 kmph and many other parts where they near the 300 mark as well.
“Most of a lap of Hockenheim is taken at high speeds in a Formula One car, but there are notable slow corners,” says Hamashima. “Turn Six, which is the slowest corner, comes immediately after the fastest corner, meaning that our tyres will be subject to many different stresses during the course of a lap.
“For instance, the heavy braking into Turn Six generates a lot of heat, especially as teams run with low levels of downforce, and this comes at a time when the tyres are already very hot from the lateral forces from Turn Five, so the tyres have constant severe forces acting on them.
These forces do not let off for even a second. “Even on the exit from Turn Six, because of the low downforce set-ups, traction from mechanical grip is called upon and the tyres continue to suffer.”
All that was for just one part of the track. The tyres though, have to prove their capability over the entire track but for Bridgestone, it is work that they are accustomed to after all, it isn’t the only circuit that is hard on the wheels.
“Previously, we have seen the German Grand Prix at Hockenheim be one of the hottest races of the year,” explains Hamashima. “We bring the hardest compounds in our dry tyre range and although there could be problems with overheating due to the high ambient and track temperatures and high stresses placed on the tyres by the circuit, blistering should not be a big problem.”
Recent weather in Hockenheim has been far from that requiring sun lotion, with rain being a feature of the recent test there. “Our current tyres have a wide temperature working range, so even if it is cooler there should be no problems,” says Hamashima, “especially as so much heat is generated in the tyres themselves due to the circuit layout.
“And, of course, our wet and extreme wet tyres deliver good performance in difficult conditions, just as we saw during the recent British Grand Prix.”
Hockenheim, like many veteran tracks, has undergone a lot of structural change, in the track layout, over the years. First held in 1970 the track came into use only when Formula One drivers decided that the 14-km long Nurburgring circuit wasn’t safe. Nurburgring underwent a makeover and things returned to normal until 1977, when Hockenheim got its second race.
Hockenheim was the venue for all German Grand Prix races between 1977 and 2006. The circuit was 6.8 kilometers long and was famous for its long straights and high speeds that led drivers through the forests. The circuit underwent major changes after the 2002 season and the long straights gave way to a more curvy, and slower, track.
“The previous layout of Hockenheim was very distinct, with three long straights over the course of a lap,” explains Hamashima. “This meant that the track was seen as being a ‘power’ circuit where a team’s engine and engine power were tested to the maximum. However the long straights also presented some interesting areas for consideration for our tyres as they meant that tyre pressure was particularly critical, especially if pressure were too low.”
Low tyre pressure on long straights means that the tyres get heated up at a time when they should actually be coolnig down, something they would do if the pressure was right. This would generally cause, what is known as “Standing Waves” with extremely high temperatures on the tyre’s shoulders. “The long straights put a lot of stresses through the tyre’s construction, and low pressures would increase the forces through the tyre, requiring extra vigilance from teams about tyre pressure,” explains Hamashima.
Converting the straights into chicanes meant a heavier usage of brakes and thus, more heating for the tyres. “When we have heavy braking and low levels of downforce, the tyre is absorbing most of the energy and getting hot as a result,” says Hamashima. “This is different from heavy braking when there are high levels of downforce where the aerodynamics of the car greatly assists with the slowing.”
Hockenheim may not be the same speedy circuit that it once was but in its current shape, it has a new set of problems for the drivers to tangle with.
“Of course, it is interesting every time we visit a track that is new to us, or a track like Hockenheim that we didn’t race on last season. Last year we raced at the Nurburgring, and the weather we faced made for an exciting event,” says Hamashima. “By not always visiting the same venues every year we do have an additional challenge for our engineers and the teams and drivers, so from this respect we benefit.”