Police, companies offer tire comparisons

Winter driving is not just about driving on snow or ice; it is about grip under all road and atmospheric conditions.

OPP Constable Mark Cloes has passed along some infor­mation people might want to con­sider about using winter tir­es or all weather tires.

In some cities, winter driv­ing means mostly cold dry pave­ment. In rural areas, with the wind blowing across the open fields, it may cause the temperatures to plum­met even more; it may also allow snow to accumulate in small drifts on the road. As temperatures drop below 6C to 7C, all-season tires start to lose grip, while winter tires gain grip. Grip means more of a safety margin for the driver and passengers.

The four main physical prob­lems of winter driving that tires must endure are cold, wet, snow, and ice. Any of those is cause for con­cern. When two or more combine, drivers can expect a long commute home.

The county OPP of­fers tire tips for autos in the winter that will en­hance traction. 

One problem in winter driving is there is almost always a film of water between the tire and snow or ice. That film is created by the weight of the car compressing the snow or ice. That film acts as a lubricant.

The next issue to solve is at what temperature was that phe­nomenon at its worst. There are two temperature ranges where mini-hydroplaning occurs. The first is at a temperature be­tween -6C to 0C. There con­ditions are perfect for pres­sure from the tire to create water.

The second occurs when ambient temperatures are above freezing and road ice is melting on its own.

Tread designs are divided into grooves and sip­es. Grooves are the tread design or the cuts through the face of the tire, and the sipes are the treads or cuts leading to the side of the tire.  A winter tire with a high void area works best on snow. A tire with a low void area works best on ice.

Void area is the open area in a tire’s tread. Grooves and sipes that are open are considered void area. (Sipes are thread-like slits in the tread that help evacuate water for better wet traction and act as biting edges in snow.)

Most tire manufacturers’ win­ter tires use a special blend of rubber compound for the winter tires. It bonds better with the road and enhances traction in wet and snow. That compound has better low-tem­perature flex capabilities and is more abrasive resistant for longer tread life. Tire manu­facturers increase the sipes for winter tires compared to sum­mer tires to help expel water from under the tires, as well as better traction on snow and ice while cornering.

To provide extra grip, some manufacturers have added ab­rasive material into the tread rubber. Those bits of grit are grabbers on ice, and will actually cut into the ice when stopping. They actually leave small scrapes on the ice .

To ensure the grit bits do not fall out with the first forceful tire spin, they are chemically bonded into the rubber.

All of those things have been changed and made special for winter driving and with better traction, comes better grip and then better stopping power.

Stopping distances

In winter driving , it takes all vehicles long­er to stop on snow-covered roads.

After looking at the chart by the Ministry of Transportation on stopping ability comparing all season tires as compared to winter tires – winter tires win.

Many tire manufacturers sell winter tires, but Cloes added, “Please don’t mix and match. Four of the same is your best and safest option. There is of course an added expense of those tires, but isn’t your safety worth that expense?”