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Bridgestone tyre' s development

Bridgestone tyre' s development

Bridgestone tyre' s development

MotoGP tyre engineers are working in areas of extreme performance, where small differences are magnified to extremes. It's the nature of the surface grip that makes the difference, and quite small changes can mean big variations in levels of tyre performance.

The strongest tracks for Bridgestone last year were Motegi in Japan and Sepang in Malaysia, where Bridgestone-shod Ducati Marlboro rider Loris Capirossi was dominant. These two circuits have something in common - a relatively high coefficient of friction, or what engineers call the µ (Mu) value.

Of course, other tracks are at the opposite end of the scale, and here the Bridgestone runners found their advantage nullified. It's these surface differences that make racing such a challenge for the tyre designers, and also worthwhile as a real-world development tool.

"Development for the current season has been focused on improving performance at the low-µ circuits, like Catalunya, Donington Park and Qatar," explained Bridgestone's team co-ordinator Motoharu Kezuka. "We have been targeting those problem tracks."

There is no revolution involved. "We have been working on the same line, the same basic theory of development, from the beginning," he continued. The search for the right tyre to suit the low-µ tracks is to find the correct combination of the existing ingredients.

"The main part would be in rubber compounds," Kezuka said. "It's the combination of rubber, synthetics and chemicals. It's quite simple: you have to find one that matches the circuit. We're constantly trying new recipes of different compounds to put with various constructions."

The frictional properties of each circuit obviously have a lot to do with the ingredients of the asphalt. "Sometimes crushed seas-shells are used, along with various cements," continued Kezuka. "From one country to another, the composition of the stone chippings used changes. All the ingredients have different character of friction."

This in turn influences the performance of the tyre, which can be seen in the temperatures. "Every rubber compound, every tyre, has an optimum working temperature, that is influenced by firstly ambient temperatures, and secondly by the friction against which the tyre is working," said Kezuka. "There are quite big differences in this from one track to another."

Aside from the work done in the laboratory, using data gathered from the circuits in previous years or during testing, there is a lot of trial and error. "We bring a lot of different specification tyres to each race. The first two days of the weekend are spent trying to find out what works best," he said.

And of course they are aiming at a moving target – because of temperature variations during the course of the day, and from day to day. It is, as Kezuka said, perfectly simple. You just have to make the right tyre for the job. If only it was as easy as it sounded, however, then making MotoGP tyres would hardly be such an exciting and fruitful challenge for the Bridgestone engineers.

MotoGP, 2006

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