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- Mud Flaps
- Engine Tuning
October 25, 2007
Ever since the introduction of the automobile, snow-packed and ice-covered roads have represented some of the most challenging winter driving conditions in North America. This has led ingenious inventors and creative companies to try everything from aggressive tread designs to bolts, spikes, crushed walnut shells, coiled wire, metallic studs and exotic tread compounds to provide the snow and ice traction needed to make winter driving less hazardous.
And while the evolution of successful technologies has typically provided more snow and ice traction than the previous ones, there have always been compromises and room for improvement. For example, many early snow tires are best remembered for aggressive tread designs that whined or growled whenever driven on dry roads. And while studded snow tires brought measurable improvements in ice traction compared to the non-studded snow tires of their day, driving studded snow tires on dry roads caused so much surface deterioration that most states restricted or prohibited their use.
Surprisingly one of today's most successful technologies is also one of the smallest. Bridgestone introduced Blizzak Studless Ice & Snow Winter / Snow tires to North America for the 1992 winter season. What made Blizzak tires unique was that they were the first winter / snow tires in North America to feature a Multicell tread compound containing microscopic pores to deliver increased traction on packed snow and ice without damaging the roads. Now 15 years later, Bridgestone introduces its third generation of studless winter / snow tires, the Blizzak WS60.
To get a better idea of how the new Blizzak WS60 compares to other popular Studless Winter / Snow tires, as well as a Studdable Winter / Snow tire, Tire Rack team conducted a Real World Road Ride and Ice Rink Performance Drive, comparing the Bridgestone Blizzak WS60 with two other choices from its Studless Winter / Snow tires category, the Dunlop Graspic DS-2 and Michelin X-Ice, as well as a studded winter / snow tire, the Firestone Winterforce. Our evaluation used new, full tread depth 205/55R16 tires mounted on 16x7.5" wheels.
Since our Real World Road Rides include 65 mph expressway speeds and would be our team's first evaluation, we had to precede them by completing our winter stud manufacturer's recommendations for breaking-in the new studded winter / snow tires. The winter stud manufacturer's instructions stipulate relatively slow driving of less than 31 mph (50 km/h) without hard acceleration or braking for the first 62 miles (100 kilometers). This permits the lubricant used to install the studs to escape and/or evaporate while it allows the tread rubber to better conform to the studs' shape. By the time we completed this test, we had run each tire approximately 500 miles on the road and spent 14 hours driving on ice. In spite of the 65 mph expressway speeds and spinning and sliding the tires on the ice, our post-test inspection revealed we didn't lose or loosen one stud.
NOTE: Studded winter / snow tires are not recommend for high speed driving because high speeds, as well as excessive tire spinning, can cause studs to be ejected from the tire.
What We Learned on the Road
Our 5.6-mile loop of expressway, state highway and county roads provides a great variety of road conditions that include city and highway speeds, smooth and coarse concrete, as well as new and patched asphalt. This route allows our team to experience noise comfort, ride quality and everyday handling, just as you would during your drive to school or work.
Recognizing that the design features that increase a winter tire's snow and ice traction (aggressive tread design, pliable tread compound and deep original tread depth) also reduce their dry and wet road responsiveness, we "recalibrated" our handling expectations and drove the tires accordingly. This required a little earlier steering input and more steering lock than normally needed for the summer and all-season tires we test.
The Michelin X-Ice was considered the most capable of the group on dry roads and drove almost like an all-season tire. The Blizzak WS60 offered a good blend of road manners but couldn't quite match the responsiveness of the X-Ice. Tread squirm could be felt in the vehicle when driving the deeper-treaded Graspic DS-2 and the studded Firestone Winterforce felt a bit vague and the least connected.
While all of the tires felt a little firm over larger road irregularities, the Blizzak WS60 provided the best overall ride quality of the group, followed by the Firestone Winterforce, Graspic DS-2 and the X-Ice.
While all of the studless winter / snow tires were a little louder than typical all-season tires, the Blizzak WS60 didn't generate tones in any specific frequencies and its white noise was considered the most agreeable compared to the more distinct tones produced at some speeds by the Graspic DS-2 and X-Ice. None of the studless winter / snow tires produced noise quantities or qualities that were considered objectionable, however the same cannot be said for the Firestone Winterforce studded tires, where the studs generated so much noise that they were considered objectionable by many members of our team.
What We Learned on the Ice
In place of our normal test track drive, our team went to a local ice rink to experience these tires' traction and handling. While it was 90° Fahrenheit outside, the ice rink provides the appropriate conditions to experience tires in a controlled environment because the ice is as cold and slippery as intersections will be in the middle of winter.
However because of the tires included in this test (one studded tire and three studless), the rink's icy surface ultimately represented that of a crowded intersection where everyone was in a hurry and one out of every four vehicles was equipped with studded tires. And because some wheel spin was inevitable, the studded tires left their mark by rutting the ice and deteriorated its normally smooth surface. While the rutted ice reduced the footprint contact area of all of the tires, it also probably represented a worst-case scenario for winter road conditions.
Our acceleration runs began with each car lined up with its rear wheels on the goal line. We then recorded the time it took for the car to cover the final 60 feet to the center of the rink as the car accelerated as fast as its tires and traction control would allow.
Establishing the Firestone Winterforce studded winter tire's 60-foot acceleration times as our basis of comparison (and assigning it a traction index of 100), we found that the slightly faster Michelin X-Ice earned a traction index of 101, while the faster still Dunlop Graspic DS-2 earned a traction index of 108, and the new Bridgestone Blizzak WS60 tires completed the course with the fastest time and earned a traction index of 115. We were surprised when all three of today's high-technology studless winter / snow tires were able to provide more acceleration traction on ice than the studded winter / snow tires!
Then we demonstrated each tire's ability to corner on ice as the car negotiated a simulated 90-degree right hand street corner while maintaining a predetermined speed. With traffic cones set every 6 feet along a line representing the center of the road being turned onto, we could determine how tight an arc the tire's traction would allow the car to maintain.
During the cornering test, the Blizzak WS60 consistently completed our 90-degree right hand street corner at the target speed without making contact with any cones, followed by the Graspic DS-2 and the X-Ice. Surprisingly, the studded Firestone Winterforce had the most difficult time completing the corner.
At the end of this test we learned that today's advanced tread compound and design technologies exceeded that of the traditional traction of studs on ice. Considering that only about six studs are in contact with the ice at any one time as the tire rolls across its surface, we found that the weak link is the ice itself, which chips away during contact with the studs. The ruts left on the surface of the ice showed that the studs were making contact, but the ice itself just wasn't strong enough to be considered a good traction partner for the tires.
Especially considering the unacceptable noise generated when studs contact dry and wet roads, we recommend using today's advanced tread compound and design technologies to drive through snow and on ice in winter.
Bridgestone Blizzak WS60 (Studless Ice & Snow): The Blizzak WS60 is Bridgestone's Studless Ice & Snow winter tire developed for the drivers of coupes, sedans and family vans that want more winter driving control and confidence than available from any all-season tire. Blizzak WS60 tires are designed to enhance wintertime traction on wet and icy roads, as well as in slush and snow. Read More.
Dunlop Graspic DS-2 (Studless Ice & Snow): The Graspic DS-2 tires represent the 2nd generation of Dunlop Digi-tire Studless Ice & Snow winter / snow tires designed to deliver traction for drivers who want enhanced control in snow and on ice. Graspic DS-2 tires are available to fit many vehicles including coupes, sedans and family vans.
Michelin X-Ice (Studless Ice & Snow): The X-Ice is Michelin's Studless Ice & Snow winter tire developed for the drivers of coupes, sedans and family vans that want a boost in winter driving confidence. X-Ice winter / snow tires are designed to combine X-tra ice and snow traction with enhanced handling on wet and dry roads.
Firestone Winterforce with Studs (Studdable Winter / Snow): The Firestone Winterforce Studdable Winter / Snow radial was developed for the drivers of domestic and imported sedans, vans and light trucks. When studded, the Firestone Winterforce is designed to deliver outstanding value at an affordable price to provide traditional traction in snow, hard-packed snow and ice. Read More.