In the northern climates where large amounts of snow fall, there is a ritual of changing out summer tires for winter tires. These winter tires are usually much heavier and have deep grooves. Some even may contain small metal studs. Of course the heavy-duty tire may also cause poorer gas mileage, but when the snow is deep the tires' performance outranks light-duty tires.
The treads on a tire are those grooves which channel away water that may accumulate on roadways after it rains and storms. The summer tire generally has narrow grooves to quickly remove the water from under the tire as you drive. A winter tire has deeper and wider grooves. These grooves do not necessarily remove the water. The depth of the groove allows a greater surface area to come in contact with things such as mud and snow. The more surface area of the tread the greater the ability for the tire to push forward through the material.
Not all states allow the use of metal studs on winter tires. If they do, it is generally on a limited seasonal basis. The metal stud can tear up asphalt and concrete that comes under its tread. If allowed, the metal stud can greatly increase the grip of a winter tire on packed snow and ice. The studs actually dig into the surface under the tire. These metal spikes do become flattened over time but they still can grip on extremely slick surfaces. Metal studs have to be replaced with extended use. If a driver is driving out of his home state, he may have to change the tires if driving into other states that don't allow studs. Metal studded tires are very noisy on dry pavement. As the studs come into contact with the hard surface they produce a loud humming noise inside the car or truck.
Not all front wheel drive cars are capable of handling the winter tire. The deep grooves can create instability in steering when traveling at high speeds. Owners of front wheel drive vehicles should check with their dealers provided manuals on their particular model. Some car manufacturers do have specially made tires for winter weather that they have developed with certain tire companies.
