When we're working with our engineers, they say, “You're asking for everything!” and we say, “Well, yeah. That's what the customer seems to want.”
-Julie Porter, Bridgestone Touring/Eco Product Manager
Bridgestone's brand-new Grand Touring tire, the Turanza Serenity Plus, definitely reaches for the sky, aiming better the current Turanza Serenity's wet grip, quiet ride and long wear by adding in lower rolling resistance, even better wet grip and light winter performance. That's a tall order, but one that Bridgestone seems to have largely filled. The Turanza is an excellent Grand Touring tire that simply doesn't bother stopping there.
- Quiet and smooth ride.
- Industry-leading grip for a Grand Touring tire.
- Jaw-dropping wet grip in shallow water.
- I am unsure about hydroplaning resistance in deeper water.
The Turanza Serenity Plus has a very interesting set of air voids cut into the center rib. These voids are designed to swallow up tire noise by breaking up the air compression events that cause the noise to begin with. As Bridgestone engineer Mark Kuykendall put it, “Most tread noise is all about air compression”
The Serenity Plus also includes the ever-present set of self-locking sipes that are quickly becoming an industry standard on any tire that has any kind of wet or winter performance needs. By controlling tread block flex with self-locking sipes, Bridgestone's engineers are helping to control tire noise, tread squirm and high treadwear caused by too much flex.
Lastly, the Serenity Plus has a striking set of arced tread blocks offset slightly from the center of the tire. According to the engineers, this is partly functional and partly decorative. Functionally, the arced blocks tend to break up noise, and the grooves are designed to quickly evacuate water. I find the grooves somewhat confusing. Since the tires are asymmetrical rather than directional, on one side of the car these arced grooves are going to be headed in a direction that I would call backwards, forcing any water in the grooves into a channel that narrows severely before opening out to the shoulder of the tire. Because water does not compress, I do not myself see how forcing water into a narrowing channel does not cause hydroplaning problems when the water is deep enough. UPDATE: As best as I understand, the design of the grooves acts on the water by speeding it up and forcing it out of the flared ends faster, and that rubber is more compressible than water. It certainly seems to work quite well.
Bridgestone put the Turanza Serenity Plus to the test by letting us drive them on BMW 328i's on a wet braking track followed immediately by a set of diminishing radius turns. They set up the test to compare their tires against a set of Michelin's Primacy MXV4's, a strong sign of how confident they are in their tires.
On a wet braking track with three different drivers at a cruise-controlled 55 miles per hour, the tires consistently stopped substantially shorter than their competition. In lateral grip tests, the Serenity was able to negotiate a diminishing-radius turn 5-10 miles per hour faster than the MXV4 without breaking loose. In both wet and dry conditions, the Turanzas were somewhat quieter than the Michelins as well.
The Bottom Line:
The Turanza Serenity Plus is undoubtedly an excellent example of Grand Touring tires at their finest, “plus” a little bit more. In addition to the expected quiet ride, long wear and low rolling resistance, wet performance and winter capabilities are a definite “plus.” Bridgestone has every right to be proud of what they have accomplished here.
The Bridgestone Turanza Serenity Plus will be available in June of 2012 in 30 sizes from 16” to 19”.