Japan-based Bridgestone is enduring a tough year financially on higher prices for rubber and other raw materials that are essential for tyre manufacture. To meet the demands of car manufacturers, Bridgestone is investing heavily in technical innovations such as run-flats. Matthew Beecham talked with Bridgestone technical man Franco Annunziatto.

just-auto: What technical innovations and strategies will Bridgestone be pursuing now and in the future?
Franco Annunziato: The tyre business is wide and varied and at Bridgestone we have many technical innovations under development. Our involvement in Formula 1 and Moto GP has encouraged our R&D departments to be at the forefront of innovation.
In the car tyre market the innovations are mainly driven by the demands of the car manufacturers. Their evolution towards safer cars with shorter stopping distance has required us to develop tyres with improved grip at no trade off in any other area of performance, specially as far as rolling resistance is concerned.
However, one of the most important developments at Bridgestone is the continuing evolution of the run-flat tyre (RFT) where we have become a clear leader. By the end of April 2008, Bridgestone had produced world wide 10 million RFTs.
just-auto: What are the factors driving demand for run-flats?
Franco Annunziato: We recognise that there are several outside factors that are increasing the demand for run-flat tyres, such as safety and the need to make vehicles lighter to reduce CO2 emissions. We also believe that the use of run-flat tyres is contributing to environmental sustainability. Cars with run-flat tyres have no need for a 5th tyre as a spare, from the beginning to the end of the vehicles life.
just-auto: How is your run-flat business shaping-up?
Franco Annunziato: Although Bridgestone first introduced its SSR [self supporting sidewall run-flat] technology in 1986 on the Porsche 959, it was only in 1999 that the volume sales of run-flat tyres started. They were chosen by BMW as a standard fitment on several models.
Over the last six years, several car manufacturers have added run-flat tyres as a fitment on their vehicles, either as standard or optional. These manufacturers include Ferrari, Maserati, Mercedes, Toyota, Lexus, Mazda, Volkswagen, Audi and Nissan.
We are convinced that the popularity of run-flat tyres will grow. There are compelling advantages of not needing to carry a spare wheel and tools, of knowing that you don’t have to stop your car on a highway or a dangerous place, to replace a flat-out tyre, of increasing luggage space and reducing the overall weight of your car. So our strategy is to improve the performance of run-flat tyres, and meet the needs of this projected demand.
just-auto: During the past six years, in what ways have these automakers’ requirements for run-flats changed?
Franco Annunziato: Car manufacturers continually improve their technologies, and we as tyre manufacturers have to move with them. Current demands are for lower rolling resistance tyres, with lower pass by noise, with no reduction in wet grip properties, and with adequate riding comfort level.
Same as for normal services tyres, also for run-flat tyres to find the proper balance in order to meet these challenges is quite demanding since it does exist a direct trade off among some of these areas of performance.  For example, wet grip and rolling resistance.
In order to meet the overall balance of performance improvements are being made by working on several different parts of the tyre. New belt materials have been developed to reduce the distortion of the tread area. This contributes also to lowering the noise output. New rubber compounds have been introduced to improve sidewall flexibility without losing the run-flat performance. This improves the driving comfort of run-flat tyres. New tread rubber compounds have been used resulting in lower rolling resistance and therefore lower CO2 emissions.
Our passion for quality, safety and performance as well as care for the environment will ensure that our research and development teams are kept busy long into the future.

Franco Annunziatto is managing director of Bridgestone’s technical centre in Rome

See also: Global market review of automotive tyres – forecasts to 2014 (download)

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