Red Bull Racing
Tyre Talk: SPAcial Awareness
By Ian Lockwood
September 10 2009
The twelfth round of this year’s Formula One season held at Spa served up some rather interesting results, with exceptionally close lap times and an unexpected podium line-up.
As Official Tyre Supplier to the FIA Formula One World Championship, Bridgestone analyses the data it gathers after every grand prix so it can better understand tyre performance and usage.
Looking after the collating of this data is Bridgestone Motorsport Chief Engineer Jun Matsuzaki, who attends every race and oversees the Bridgestone engineers who work with the teams at Grands Prix.
In this unique position, Bridgestone are able to give an overview of tyre performance considerations at the recent Belgian Grand Prix.
“The first interesting thing from a tyre perspective is that the Belgian Grand Prix was the first time that we used the tyre allocation of our medium and soft tyres together at a race,” explains Matsuzaki.
“Although these two tyres can be seen as being next to each other in our compound stiffness range, they have different temperature working ranges.
“The medium compound is from the high temperature working range, whilst the soft compound comes from the low temperature working range of tyres.
“On the same car, with the same set-up and driver, the medium tyre would take longer to deliver its best lap time than the soft tyre, as the tyre has to be hotter from the forces and energy which go through it in its use.
“However, in Formula One, the cars and drivers are not the same and there can be many different methods to achieve what is a very similar lap time.”
Indeed, out on track over the course of the weekend both tyres were able to deliver very close fastest lap times, with the top eighteen cars separated by less than a second on Friday afternoon’s practice session.
“The times were close, however careful analysis shows that the different characteristics of the tyres suited different cars and drivers,” explains Matsuzaki.
“Spa is the longest circuit on the F1 calendar at 7 km. Just like any circuit we separate the circuit into three sectors when we look at it, and the three sectors at Spa do have very distinct characteristics.
“Also as at any circuit, car set-up is a compromise. In broad terms at Spa we can say that some competitors opt for a lower downforce set-up relative to others who go for a higher downforce configuration.
“There are many considerations when choosing set-up such as circuit layout and how the different set-ups work their tyres is one.
“As a general trend, the soft compound seemed to work well for the competitors who opted for a lower downforce set-up, whilst the medium compound suited those who opted for a higher downforce set-up better.
“The medium compound worked particularly well in sector two when used with a high downforce set-up; however this approach was not so good in sector one and three.
“In the first and last sectors a low downforce configuration works well as these are very high speed parts of the track. But if you have a low downforce set-up, you need to make use of the extra grip provided by the soft tyre for the second sector which otherwise requires higher downforce.
“The cars using the medium compound needed a higher downforce level to assist rubber penetration into the rough surface to generate extra grip from higher hysteresis* of the medium tyre, but this meant that they suffered with ultimate speed.”
The best illustration of how the combination of car, driver and tyres work is during qualifying, with grid position being a big factor in the potential race results.
“Qualifying in Spa was very interesting, and grid position is very important for the final results, especially when grid positions at the front are achieved with similar fuel loads,” explains Matsuzaki.
“The track temperature increased by seven degrees during qualifying at Spa and this made the decision of which tyre to use very difficult. Illustrating this we saw the fastest two drivers use the soft compound, and the third fastest driver use the medium compound.
“Q3, which determines the top ten, is a difficult session as drivers have to qualify with heavier fuel loads. A heavier car works the tyres differently, so this has to be factored into tyre choice.”
The race sees all the knowledge gained over the weekend put into practice, but it’s still an evolving track surface, and the temperature can change.
“In simple terms, it’s a very complex topic,” explains Matsuzaki. “There are so many variables involved that there is never an easy answer. However, this is part of what makes motor racing so exciting for so many people.”
Formula One heads to Monza next, where the same allocation of the medium and the soft tyre will be used.
“Monza is generally seen as a more severe circuit than Spa due to its continual high speeds, so we could see different behaviour between the tyre compounds, but in motor racing you can never be 100% sure of any prediction.”
* Hysteresis is rubber deformation through molecule movement.
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