Our question from Jesh: Why do tires have different treads?

We asked for help from our friends at Bridgestone. Mark Kuykendall, Engineering Manager of Bridgestone Passenger/Light Truck Tires was kind enough to give us the answer:

The overall tire design is based on the required (or requested) performance of the car for which it is intended. Performance cars usually require more aggressive handling tire designs, luxury sedans focus on comfort and noise, and broad market cars are usually somewhere between. Rubber compounds are used in conjunction with tread designs to fit the design characteristics needed for a particular fitment. One would generally use a more aggressive tread design on a sports car because handling is a higher priority than noise/comfort. High performance tires are generally wider and thus are more prone to hydroplaning, so a directional tread pattern might be applied to improve this specific performance parameter. Aggressive patterns are not generally used on luxury cars because they typically generate more noise and comfort/noise are a high priority on these cars. A tire designed for a luxury car will have not only a less aggressive tread pattern, but may also a different casing shape and construction. Broad market cars generally require a more balanced set of performance parameters which include higher tread mileage.

So, the bottom line is that the tire (overall design, including tread design) is based on the intended use of the vehicle and we use those features and technologies that best suit the required performance.

SOME DETAILS:

Conventional sipes are wide at the top, narrow at the base and decrease in size as the tread wears down, sacrificing wet performance with tire wear. Thus, as a conventional tire wears, it loses its tread pattern and looks more and more like a racing slick. Wet performance suffers, because shallower, worn tread channels lose the ability to evacuate water efficiently. This means more water comes between the tire and the road, resulting in ess actual contact and reducing wet traction and handling.
Bridgestone/Firestone's Key Hole Sipe is a tread pattern feature that helps solve these problems. A Key Hole Sipe is a slot with a cylindrical channel at the base. In a cross section of the tire tread, this slot-and-channel configuration resembles a key hole. As the tread wears, the "key holes" emerge to help ensure a consistent tread pattern. These sipes help maintain continued wet performance and new tire appearance.

Power-V is a tread pattern design born of Firestone's Indy® technology for rain tires. By dispersing water to the sides of the tire, the v-shaped pattern allows better water discharge and improves wet performance. The Power-V pattern elements incorporate a high/low angle approach to better discharge water from the area in contact with the wet road.

Conventional tires evacuate water in a straight line. VRG (Variable Radius Groove) is a tread design that controls water displacement with a high-volume, side-to-rear spray. This unique pattern maintains a larger contact patch, which delivers excellent wet grip and dramatically reduces the risk of hydroplaning.

Uni-Directional Pattern is a tread pattern design that maximizes both wet and dry performance, as well as other tire characteristics. By specifying that the tread pattern is to be mounted on the vehicle in a single direction only, the many design compromises found in conventional tires which can be mounted in two directions are eliminated. This gives us the ability to include a wider variety of specific performance characteristics such as high resistance to hydroplaning in each tire.

Spiral Wrap™ is a continuous nylon wrap that encircles the whole tire. Spiral Wrap provides a higher level of uniformity, helping the tire hold its original shape, and enhancing performance, which helps achieve high speed capability

For more information, check out their website HERE

Thank you Mark and Bridgestone!