Myth 1: If your vehicle has front-wheel drive, you only need two winter / snow tires.
On a front-wheel drive vehicle, the front tires do the steering, accelerating and most of the braking. If the front tires are doing the majority of the work, how important could those rear tires be? When driving in a straight line, they're not so important, but when it comes to turning, it's a different story.
When making a turn, the front wheels initiate the change in direction, but for the driver to retain control, the rear tires need to follow accurately behind. If the front is gripping and the rear is sliding, the rear of the car wants to continue in a straight line while the front follows the intended path. This can lead to loose, tail-out oversteer, and if not quickly corrected can cause a complete spin-out.
Stability control systems that are designed to prevent spins and loss of control can only work to optimize the available traction. They can't create traction that doesn't exist. If the rear tires aren't gripping, stability control is often not enough to save a spin.
We tested this myth using Honda Civics on an ice rink to demonstrate the difference between two and four winter / snow tires on a FWD car.
To view our complete test results, read "Why Gamble With Winter Tire Selection When Four of a Kind Always Beats Two Pair?".
Myth 2: If your vehicle has rear-wheel drive, you only need two winter / snow tires.
Two winter / snow tires on a rear-wheel drive vehicle used to be a common configuration. There are two main changes that explain why this is no longer the case.
First, snow tires have improved greatly over the years, therefore the difference in traction is much greater. When winter tires were less effective, they were only giving a boost in traction to the drive wheels to keep people from getting stuck in the snow. Now the difference between winter and all-season tires is big enough that there would be a more obvious imbalance in traction. There have been cases where the traction of the rear wheels pointing straight ahead have overpowered the front wheels' effort to turn, causing vehicles to plow straight ahead into obstacles or incoming traffic while attempting to turn.
Second, there's a much greater emphasis on safety today than there was in decades past. You or your parents may remember the days when seatbelts were optional, dashboards were made of metal, airbags were unheard of and safety mostly meant "don't hit anything." Things that would be dangerously negligent or downright illegal today used to be viewed as perfectly normal.
In summary, the front wheels are responsible for the steering and most of the braking, and it doesn't make sense to shortchange them when it comes to winter traction.
Myth 3: Bridgestone Blizzaks only give half the amount of winter service because the bottom half of the tread is a regular all-season compound.
Like many myths, this one is a distortion of reality. The first 55% of a Blizzak tire, like the WS70 for example, uses the winter Multicell compound. There are taller wear bars that'll indicate when the end of the compound is close. Below this is not an all-season compound, but a standard winter compound. Because the Multicell compound is more flexible, using a standard winter compound for the base makes the tread more stable.
A major point that is often overlooked is that any winter / snow tire, regardless of compound, loses much of its effectiveness when the tread is too shallow. It's not recommended to go through a winter with snow tires of any brand that start the season with less than 6/32" of remaining tread depth.
Blizzak tires will provide optimum traction until they reach the point where they or any other tire should be replaced. Below that depth they're still a winter tire, but the lack of tread depth will compromise effectiveness in deeper snow.
For additional information on this line of tires, read "Bridgestone Blizzak FAQs."