| A tire or tyre is a covering provided on the | | | | ice, snow, mud and sand. |
| circumference of wheels of vehicles. The | | | | |
| functions of tires is to dampen oscillations | | | | Grooves. Grooves are voids on the tires |
| due to uneven surface of the road, to prevent | | | | designed to facilitate dispelling of water or |
| wear and tear of the wheel, to provide a high | | | | snow. Deeper grooves provide better handling |
| friction bond between the vehicle and the | | | | and control of the vehicle in snow. |
| road for proper acceleration and handling of | | | | |
| the vehicle. They are usually made of | | | | Void Ratio. Void ratio is related to the |
| synthetic rubber. | | | | amount of rubber coming in contact with the |
| | | | road. It is defined by the voids or open |
| Snow tires are special tires designed to run | | | | spaces on the tyre. A high void ratio |
| on snow, ice, wet roads, sleet, slippery | | | | accelerates the potentiality to drain water. |
| roads and mud. They have better traction and | | | | For snow tires a high void ratio is required. |
| handling properties. Snow tires differ from | | | | |
| regular tires in the following ways: | | | | Aquaplaning. One of the functions of tires is |
| | | | to remove water from the treads on wet roads. |
| Hardness. They are made up of softer rubber, | | | | When the tire rotates, the treads push water |
| which heats up quicker. The softness and | | | | into grooves and sipes, from where the water |
| hardness of tire rubber depends upon the | | | | is pushed out. If the water does not go out |
| amount of carbon black in it. For summer | | | | properly then the vehicle slides which may |
| tires, the amount of carbon black is more and | | | | cause accidents. This sliding of the tire on |
| for snow tires the amount of carbon black in | | | | water is called aquaplaning. Hence the depth |
| the rubber is less. Rubber becomes brittle at | | | | and pattern of treads is very important. |
| lower temperatures hence summer tires are not | | | | |
| suitable to be used in winters. | | | | Metal studs. Most snow tires have metal studs |
| | | | fabricated in the tread. This provides better |
| Treading. The crown or the outer perimeter of | | | | grip on snow and ice. A place where the |
| tires has jagged pattern on it known as | | | | weather is extreme, the law makes it |
| tread. The function of tread is to provide | | | | mandatory to use snow tires. However snow |
| grip during rain or snow. The summer tires | | | | tires are extremely noisy and wear out fast |
| have smaller tread on them. The snow and mud | | | | on dry roads. Further, they wear out the road |
| tires have larger tread blocks on them hence | | | | also. |
| they are noisier. | | | | |
| | | | Markings on Snow Tires. The tires designed |
| Sipes. Sipes are small slits provided on the | | | | for Mud and snow are marked with M&S. the |
| sides of tires to provide flexibility to | | | | icon of mountain and snow flake designates |
| tread blocks on the tyre. The function of | | | | that the tire meets snow testing standards of |
| sipes is to disperse water and snow. They | | | | American Society for Testing and Materials. |
| improve traction by providing an additional | | | | It mandates that snow tires should have a |
| biting edge to the tyre and are helpful on | | | | traction index of more than 110. |