Imagine you are riding a car when it’s raining. At a low speed, you don’t feel any difference from normal riding. But at higher speeds, one can feel the speed of the car getting affected. This is because of a phenomenon called ‘water planing’. Water resists the ply of the tires on the ground by forming a block on the area between the front of the tire and the ground. This affects driving performance increases the possibility or skidding. Rain tires are sometimes designed to have a smaller diameter. This helps the tire to rotate faster and displace more water overcoming centripetal force. Sometimes they are also narrower than other tires. This reduced footprint of the tires helps avoid hydroplaning.
Water displacement is the first and foremost job of a wet-weather tire. Multiple features of the wet weather tires aim at providing this. One such feature is the rain groove. How does a rain groove work? The area of the tire that comes in contact with the earth is called the contact patch. This contact should always remain for movement to happen. Because of this, the area of the tire that is in contact with the road is made to flatten and then regain the normal shape. In dry conditions, this happens normally with no obstruction.
But in conditions like when it is raining, this process gets affected. Maintaining the same amount of contact with water on the ground is difficult. When there is an excess amount of water collected in the road, hydro planing can go up to the extent of completely disconnecting the tire from the ground. Hydroplaning causes a lot of accidents every year.
A rain groove pulls water away from the area of contact of the tire with the ground. To combat water on the roadway and lower the risk of hydroplaning, tires are fitted with rain grooves. This is achieved by properly designed patterns and correctly arranged voids. The patterns are angled so that water is directed away from the center of the tire whereas the voids serve as a channel to displace the sidelined water.
Rain tires are made from soft rubber. Softer rubber helps in having a better grip in wet conditions and they also help in building up heat inside the tire. The rubber used in wet weather tires comprises oils and chemicals. When introduced to heat, the tire tends to become sticky due to these elements and start to deteriorate. The softer the tire is, the weaker it is when exposed to heat. One of the methods drivers use to avoid tire deterioration while wet conditions are getting dried up is driving purposely on stagnated puddles of water to cool the tires.
Advantages of wet-weather tires
Improved safety- wet weather poses some of the most dangerous driving conditions; from reduced visibility to slippery roads during winter and autumn months. These tires provide improved braking performance and traction on these wet roads for safe riding.