NICE, France (Jan. 20, 2016) — Bridgestone Corp. has developed a slightly tweaked version of its DriveGuard run-flat tire for the European region, one that offers higher performance ratings than conventional run-flats under the European Union's tire labelling regulations.
Unlike the all-season version launched in North America two years ago, European drivers will be offered summer and winter versions of the Driveguard — more attuned to the wet driving and cornering conditions experienced in the region, Bridgestone officials said at the product's launch this week in Nice. It's being billed as a premium touring tire with extended mobility, rather than a “run flat” per se.
At the heart of the DriveGuard's performance is a treated polyester fiber reinforcement that Bridgestone claims overcomes the ride-comfort issues that have limited run-flats to a niche segment of the market over the past 15 years.
The polyester fiber is treated with a coating material developed by Bridgestone to help ensure that reinforced sidewall supports the vehicle upon sudden air loss. The tire is rated to be driven in deflated condition at 50 mph for 50 miles.
This treatment enables the polyester, which has a softening point of around 140 degrees C, to withstand the deflated driving conditions, when temperatures within the rubber can rise to 180 to 200 degree C.
The reinforcement technology also allows the use of thinner rubber layers to enhance the ride performance of the extended mobility tire — while durability and rolling resistance are enhanced by the use of an optimized nano-filler/compound system.
Thus the DriveGuard carries an A rating for wet grip performance and C rating for rolling resistance.
The tire features another Bridgestone proprietary technology: the use of sidewall ribbing or “cooling fins” that can reduce sidewall temperatures by 20 degrees C, channeling heat away to the tire rim when driving in a deflated state.
Bridgestone is producing the DriveGuard its Poznan, Poland, plant. It will be available in 19 summer and 11 winter sizes, ranging from 185/65R15 to 245/40R18.
The summer tire will be available from March in much of Europe from March with sales of the winter tire to follow in June, according to a Bridgestone spokesman.
Due to capacity issues, customers in Scandinavia and Eastern Europe will not be offered the product until next year, the spokesman also pointed out.
Eduardo Minardi, executive chairman of Bridgestone Europe/Middle East/Africa, said at the launch: “Our revolutionary new technology will considerably contribute to road safety and give drivers additional peace of mind and convenience while on the road.”
While runflats are generally supplied as optimized factory fitments, the new tire can be fitted to most cars equipped with tire pressure monitoring systems (TPMS) devices — mandatory on new cars in Europe since November 2014.