Coming from the brand that sells Potenza-, Alenza-, Turanza-, and Ecopia-branded rubber, the name of Bridgestone’s DriveGuard tires is obviously less Latinate, but it’s also rather straightforward. DriveGuard encompasses a new family of replacement tires aimed at the bestselling family-sedan segment, so touring rubber with an all-season, M+S rating. But here’s the notable part, and the thinking behind the name: DriveGuard is the first aftermarket run-flat intended for cars that came from the factory with standard tires.Run-flats have long taken flack for the rock-hard ride quality that comes as a result of their necessarily stiff sidewalls. Bridgestone, with the DriveGuard, intends to slay this particular beast. Through complex manipulation of the rubber compound at the molecular level, Bridgestone claims to have made a run-flat that doesn’t compromise ride. The fancy rubber works to shed heat on its own, working in tandem with patented cooling fins on the tire sidewall that generate vortices of air to further cool the tire.
Dissipating heat is extremely important, as heat destroys a tire whether it’s filled with air or flat. As soon as air pressure vacates a tire, the carcass is pinched and bent much more than it is under normal circumstances, which increases the temperature of the rubber. Eventually, the heat breaks down the rubber to the point that it falls apart. Traditional run-flat construction—which you can see here, where we sliced one open—combatted tire deformation and subsequent breakdown by adding more and stiffer material to the sidewalls, hence the firm ride.
In a controlled test, Bridgestone let us drive cars fitted with the DriveGuard and a few of its conventional tires that serve the same market, including the Bridgestone Turanza Serenity Plus. As Bridgestone claims, we couldn’t detect any compromise in ride quality, although we’d like to have sampled the tires back-to-back on the cratered roads near our Ann Arbor offices. Still, Bridgestone is so confident in the technology that it’s offering a 30-day trial: If you buy a set and hate ’em, bring the tires back and exchange them for another set or get a refund. Plus, if you happen to test the run-flat capability within the first year (or 12,000 miles) Bridgestone will completely replace the tire if it isn’t repairable. (With run-flats, sometimes the inner sidewalls are too damaged to safely return the tire to the road.)
As with most all-season touring tires these days, the DriveGuards come with a fairly lofty tread-wear warranty. Depending on the speed rating of various fitments, it’s either 50,000 (W-rated) or 60,000 (H- and V-rated) miles. Once evacuated of air, the tires are said to be capable of 50 miles of operation at up to 50 mph, which is an ISO standard for run-flat capability. With little or no air pressure, the DriveGuard sidewalls are designed to perform like those in a conventional tire inflated to 15 psi.
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If you’re wondering why this is the first big push for aftermarket run-flat sales, it comes down to tire-pressure monitoring systems (TPMS). Run-flats require TPMS because, well, without it, many drivers might not notice their tire pressure is dropping (or absent). TPMS has been required on all new cars since 2007, and Bridgestone expects a whole lot of those new cars will be due—or past due—for fresh rubber this summer.
Bridgestone hasn’t announced final pricing yet, but it told us that DriveGuard tires will cost about as much as its Turanza Serenity Plus line, which makes sense as the two tires share a tread compound. The majority of the 35 available sizes at launch will fall between $400–$800 a set, or right in the ballpark for a premium tire.
The Bridgestone DriveGuard RFT goes on sale at the beginning of May. We’re interested to see how many folks jump at the chance to fit run-flats, especially given that there’s little to no degradation in ride. We think the average Accord, Passat, Fusion, or Altima owner—especially in pothole-pocked Snow Belt states—will be excited at the possibility that they won’t have to change a tire on the side of a busy expressway. Reported by Car and Driver 8 hours ago.