by Jim Kerr
As we enjoy the beautiful warm days of Fall it’s difficult to think of the cold winter ahead, but soon the snow will fly. Snowy roads make for poor traction and until drivers get used to it again, there will be a rash of fender benders. Most of these accidents could be avoided by driving slower, attentive driving, and the right tires.
The right tires. For winter driving, the optimum tire is a winter tire. Sure there are all-season tires out there and most cars come with them from the factory, but for the best traction on snowy, icy roads, nothing beats a tire made specifically for winter driving conditions. Winter tire technology is changing as fast as the seasons and every year there are new design features to provide extra traction. One of the newest tires on the market is Yokohama’s Ice Guard IG10 winter tire. After trying this tire out on a variety of road conditions, this is what I discovered.
Winter tires are used to provide traction under extreme conditions, but most of the time we drive our vehicles on dry winter highways. How can a tire do both? Stephane Morel of Yokohama had the answers. For winter traction, several technologies are used in Yokohama’s Ice Guard IG10. Silica rubber compounds, shelled micro-bubbles and three-dimensional Pyramid Sipes all combine to grip an icy road. Let’s look at how each adds to the traction.
Designing tire compounds is part science, part physics and a little bit of black magic. A typical passenger car tire will have about 55% synthetic rubber and 45% natural rubber while a race tire may have 65% synthetic rubber and 35% natural rubber – but there is much more than just rubber. A common all season tire might weigh about 21 pounds. Of this weight, about 6 lbs consists of five different types of synthetic rubber and another 4 lbs. of eight types of natural rubber. Eight different types of carbon black will weigh up to 5 pounds while 3 pounds will be made up of more than forty different chemicals, oils, pigments and waxes. Finally, steel for belts and sidewall beads add another 2 pounds and one more pound consists of polyester and nylon. By varying proportions of these ingredients and adding small amounts of additional substances, tire manufacturers can build a tire for specific road conditions.
Yokohama’s Ice Guard tires as well as some of their performance tires use Silica added to the carbon black for additional traction. Zeruma, a special processing agent developed by Yokohama, enables the silica to mix evenly with the carbon black for more uniform traction.
Shelled micro-bubbles in the IceGuard tire are small bubbles in the rubber that break open as they come in contact with the road surface. The bubble space creates suction that sucks up water off any ice on the road. A film of water on the ice makes it extremely slippery. For example, take an ice cube from the freezer and it can be held easily, but as it starts to melt, the water film makes it slipperier. The pressure of a tire can cause water to form on ice even when the temperatures are far below freezing. By removing the water film, the rubber can grip the ice layer. Water has the same effect on the road. As the tire rotates, the water drains from the bubbles and new bubbles are exposed as the tread wears.
Sipes are small cuts in the rubber and the edges of these cuts grip onto the irregular road surface. Shallow grooves enhance the tire’s traction until the first layer of shelled micro-bubbles appears. Deeper sipes are also formed into the tread blocks using a three-dimensional pyramid shape. This pyramid shape keeps the tread blocks stable as driving forces act on them.
How did the tires work? I switched from an all season tire to the Yokohama Ice Guard winter tire on the slipperiest day of the year. The increase in traction was incredible. While other cars were sliding around, my car was easy to control. Wet snow later in the week and dry roads later in the month proved they have excellent traction and handling in a variety of conditions.
Buying four winter tires may seem expensive, but if they save you from one accident, they have easily paid for themselves.