Tuned for winter conditions, Blizzak DM-Z3 Studless Winter / Snow Tires for light trucks provide a substantial traction advantage on ice and packed snow.

We compared three Bridgestone tires designed for light truck use, including the Original Equipment Turanza ER30 summer tire, Turanza EL42 all-season tire and Blizzak DM-Z3 winter tire. We used 235/65R17-sized tires mounted on 17"x7.5" wheels. The Tire & Wheel Packages were fitted to our 2006 model year Porsche Cayenne test vehicles.

The Porsche Cayenne lists a curb weight of 4,784 pounds and its power is distributed through a Tiptronic automatic transmission with permanent four-wheel drive featuring Porsche Traction Management.

Porsche Traction Management (PTM) distributes power using a standard torque split of 38% to the front axle and 62% to the rear; however, up to 100% of the torque can be delivered to either axle depending on driving conditions. PTM sensors continuously monitor steering wheel and throttle positions, as well as vehicle speed and lateral acceleration before determining the amount of power distributed to each axle. If one of the tires begins to lose traction, PTM uses the Cayenne's Automatic Brake Differential system to apply braking on that wheel, transferring torque that would otherwise be delivered to the slipping tire to the opposite tire instead. If both tires on one axle begin slipping, the Cayenne's electronic engine management system reduces power to reduce wheelspin.

In order to quantify the traction provided by each type of tire, we recorded the time it took for each of the Cayennes to cover 60 feet (to the center of the rink) while accelerating as fast as tire traction would allow. Due to the confines of the hockey rink, braking forces and cornering capabilities would be judged subjectively.

What We Learned on the Ice

The Cayenne's Porsche Traction Management divided the engine's horsepower between the V-speed rated summer tires, and the vehicle's acceleration time of 4.0 seconds was on a par with a rear-wheel drive sedan equipped with winter / snow tires. For that matter, the summer tire's performance appeared acceptable until its cold temperature traction resulted in the longest subjective stopping distances and lowest cornering capability.

The T-speed rated all-season tires provided a noticeable improvement over the summer tires. While their 3.4-second time (about a 15% improvement over the summer tires) was favorable, the all-season tires' cold temperature ice traction resulted in marginal improvements in subjective stopping distances and cornering capability.

The Q-speed rated studless winter / snow tires completed their run in just 2.9-seconds (about a 28% improvement over the summer tires). And even though the winter tire-equipped Cayenne was traveling faster at the onset of braking, the winter / snow tires stopped it with the greatest subjective breaking force and allowed the Cayenne to complete the cornering exercise with ease. In this case, the dedicated winter / snow tires gave the Porsche Traction Management system some real cold temperature traction to work with.

Tire Comparison

	Blizzak DM-Z3	Turanza EL42	Turanza ER30
Tire Category	Studless Ice & Snow	Standard Touring All-Season	Grand Touring Summer
60-foot Time Seconds	2.9	3.4	4.0
Traction Index*	100	86	72

*Traction Index identifies the relative performance vs. the best available (higher is better).

While not surprising, the results show the substantial advantage the studdless winter / snow tires have over performance winter, all-season and summer tires on glare ice.

The right winter / snow tires can reduce the challenge of driving your car, van or SUV in snow and on ice. Remember Dad's advice, "Nothing like using the right tool for the job!" It's your choice, make it a good one!

Product Details

The Blizzak DM-Z3 was developed to enhance a light truck's four-wheel drive systems to enhance their poor weather capabilities. So, if you want to maximize all of your light truck's winter capabilities, use Bridgestone Blizzak DM-Z3 technology to help provide the snow and ice traction you need. Read more.

The Turanza EL42 is a Standard Touring All-Season tire designed for sports sedans, sports coupes and selected sporty SUVs. It was developed to blend some of the looks and handling of a performance tire with the low noise and ride comfort associated with a passenger tire, as well as provide year-round traction, even in light snow. Read more.

The Turanza ER30 is Bridgestone's Grand Touring Summer tire often used as Original Equipment on sports cars, coupes, sedans and SUVs like the Porsche Cayenne. It was developed to blend looks and handling with good noise levels and ride comfort, as well as provide traction on wet and dry roads. Like all summer tires, the Turanza ER30 is not intended to be driven in near-freezing temperatures, through snow or on ice. Read more.