Rain tyre
Encyclopedia
Rain tyres or Wet tyres (commonly shortened to wets) are special tyre
s used in motorsport
in wet weather as opposed to a slick tyre used in dry conditions. They are very similar in many ways to the tyres found on normal road cars.
or tread
in them. This allows the tyre to quickly displace the water between the ground and the rubber on the tyre. If this water is not displaced, the car will experience an effect known as hydroplaning as the rubber will not be in contact with the ground. These grooves do not help the car grip contrary to popular belief, however if these grooves are too shallow, the grip will be impaired in wet conditions as the rubber will not be able to make good contact with the ground. The patterns are designed to displace water as quickly as possible to the edges of the tyre or into specially cut channels in the centre of the tyre. Not all groove patterns are the same. Optimal patterns depend on the car and the conditions. The grooves are also designed to generate heat when lateral forces are applied to the tyre.
. Some rain tyres are also narrower than the dry counterparts. This smaller "footprint" reduces the chances of hydroplaning.
allow an intermediate (inter) tyre. This tyre is designed to be used in conditions too wet for slick tyres and too dry for wet tyres. They are some sort of “in-between” tyre or intermediate tyre as the name suggests. They are made with rubber compounds slightly softer than slick tyres and are cut with grooves like the rain tyre but shallower to prevent excessive heat build up. However, tyre supplier Bridgestone
refers to what is commonly known as the "intermediate" tyre as the wet tyre, and to what are commonly known as "full wets" as "monsoon tyres".
Tire
A tire or tyre is a ring-shaped covering that fits around a wheel rim to protect it and enable better vehicle performance by providing a flexible cushion that absorbs shock while keeping the wheel in close contact with the ground...
s used in motorsport
Motorsport
Motorsport or motorsports is the group of sports which primarily involve the use of motorized vehicles, whether for racing or non-racing competition...
in wet weather as opposed to a slick tyre used in dry conditions. They are very similar in many ways to the tyres found on normal road cars.
Structure
Rain tyres have a specially designed structure making them better adapted for their application than any other tyres. However not all rain tyres obey the same design principles. Certain factors need to be taken into account when designing a good rain tyre, such as the:- speed of the car
- weight of the car
- power of the car
- lifespan of the tyre
Grooves
Rain tyres are cut or moulded with patterned groovesGroove (machining)
In manufacturing or mechanical engineering a groove is a long and narrow indentation built into a material, generally for the purpose of allowing another material or part to move within the groove and be guided by it. Examples include:...
or tread
Tread
The tread of a tire or track refers to the rubber on its circumference that makes contact with the road. As tires are used, the tread is worn off, limiting its effectiveness in providing traction. A worn tire tread can often be retreaded. The word tread is often used incorrectly to refer to the...
in them. This allows the tyre to quickly displace the water between the ground and the rubber on the tyre. If this water is not displaced, the car will experience an effect known as hydroplaning as the rubber will not be in contact with the ground. These grooves do not help the car grip contrary to popular belief, however if these grooves are too shallow, the grip will be impaired in wet conditions as the rubber will not be able to make good contact with the ground. The patterns are designed to displace water as quickly as possible to the edges of the tyre or into specially cut channels in the centre of the tyre. Not all groove patterns are the same. Optimal patterns depend on the car and the conditions. The grooves are also designed to generate heat when lateral forces are applied to the tyre.
Rubber
Rain tyres are also made from softer rubber compounds to help the car grip in the slippery conditions and to build up heat in the tyre. These tyres are so soft that running them on a dry track would cause them to deteriorate within minutes. Softer rubber means that the rubber contains more oils and other chemicals which cause a racing tyre to get sticky when its hot. The softer a tyre, the stickier its gets, and vice verse with hard tyres.Shape
Sometimes rain tyres are designed to have a smaller diameter than their dry counterparts. This means that the wheel spins faster and more water is thrown off the tyre by overcoming centripetal forceCentripetal force
Centripetal force is a force that makes a body follow a curved path: it is always directed orthogonal to the velocity of the body, toward the instantaneous center of curvature of the path. The mathematical description was derived in 1659 by Dutch physicist Christiaan Huygens...
. Some rain tyres are also narrower than the dry counterparts. This smaller "footprint" reduces the chances of hydroplaning.
Intermediate tyres
Some racing series such as Formula OneFormula One
Formula One, also known as Formula 1 or F1 and referred to officially as the FIA Formula One World Championship, is the highest class of single seater auto racing sanctioned by the Fédération Internationale de l'Automobile . The "formula" designation in the name refers to a set of rules with which...
allow an intermediate (inter) tyre. This tyre is designed to be used in conditions too wet for slick tyres and too dry for wet tyres. They are some sort of “in-between” tyre or intermediate tyre as the name suggests. They are made with rubber compounds slightly softer than slick tyres and are cut with grooves like the rain tyre but shallower to prevent excessive heat build up. However, tyre supplier Bridgestone
Bridgestone
The is a multinational rubber conglomerate founded in 1931 by in the city of Kurume, Fukuoka, Japan. The name Bridgestone comes from a calque translation and transposition of ishibashi, meaning "stone bridge" in Japanese....
refers to what is commonly known as the "intermediate" tyre as the wet tyre, and to what are commonly known as "full wets" as "monsoon tyres".