# Rain tyre > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Rain_tyre > Markdown URL: https://mediated.wiki/source/Rain_tyre.md > Source: https://en.wikipedia.org/wiki/Rain_tyre > Source revision: 1356694636 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Tyres used in wet weather This article relies largely or entirely on a single source. Please help improve this article by citing more sources. Find sources: "Rain tyre" – news · newspapers · books · scholar · JSTOR (March 2019) [Lewis Hamilton](/source/Lewis_Hamilton) competes through the rain at the [2016 Monaco Grand Prix](/source/2016_Monaco_Grand_Prix) using rain tyres. A **rain tyre** or **wet tyre** (**rain tire** or **wet tire** in [American English](/source/American_English)) is a racing [tyre](/source/Tire) used in [motorsport](/source/Motorsport) in wet weather as opposed to a [slick tyre](/source/Slick_tyre) used in dry conditions. It is very similar in many ways to the tyres found on normal road cars.[1] Rain tyres are not used in [NASCAR](/source/NASCAR), [ARCA](/source/Automobile_Racing_Club_of_America) and [INDYCAR](/source/INDYCAR) sanctioned races held on [oval tracks](/source/Oval_track_racing) as these races are invariably halted when the track is wet due to safety concerns regarding the large amounts of spray involved reducing visibility, as well as a lack of traction in banked corners at high speeds. ## 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 Detailed view of rain tyres equipped by [Lewis Hamilton](/source/Lewis_Hamilton) at the [2016 Monaco Grand Prix](/source/2016_Monaco_Grand_Prix) Rain tyres are cut or moulded with patterned [grooves](/source/Groove_(machining)) or [tread](/source/Tire_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](/source/Hydroplaning_(tyres)) 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](/source/Natural_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 become sticky when it is hot. The softer a tyre, the stickier it becomes, and conversely with hard tyres. When rain has stopped falling, and a track is in the process of drying, it is not unusual to see drivers intentionally driving through wet puddles and damp portions of the course, in order to cool the rubber and stave off tyre deterioration. As soon as possible, drivers will revert to slick tyres to maintain competitive speeds. ### Shape Currently, F1 rain tyres have a larger diameter than dry tyres, with the wets having a diameter of 10mm more than the slicks.[2] This increases the ride height of the car and makes it less vulnerable to aquaplaning. Sometimes[*[when?](https://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_items)*] 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 force](/source/Centripetal_force). Some rain tyres[*[example needed](https://en.wikipedia.org/wiki/Wikipedia:AUDIENCE)*] are also narrower than the dry counterparts. This smaller "footprint" reduces the chances of hydroplaning.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] ## Intermediate tyres See also: [Formula One tyres](/source/Formula_One_tyres) Intermediate tyre by [Pirelli](/source/Pirelli) at the [2016 Austrian Grand Prix](/source/2016_Austrian_Grand_Prix) Some racing series such as [Formula One](/source/Formula_One) 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 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. Former Formula One tyre supplier [Bridgestone](/source/Bridgestone) referred to the "intermediate" tyre as the "wet" tyre, and to what are known as "full wets" as "monsoon tyres". ## Invention The original invention of the rain tyre is attributed to [Uniroyal](/source/United_States_Rubber_Company), in 1969.[3][4] They were the first to understand the water-deflecting properties of directional V-shaped tread and the first to use biomimicry with the development of “Shark Skin Technology[5]”, which helps to prevent [aquaplaning](/source/Aquaplaning). ## References 1. **[^](#cite_ref-1)** McFadyen, Peter (2008). *Motor Racing at Oulton Park in the 1970s*. Veloce Publishing Ltd. [ISBN](/source/ISBN_(identifier)) [978-1-84584-164-5](https://en.wikipedia.org/wiki/Special:BookSources/978-1-84584-164-5). 1. **[^](#cite_ref-2)** ["F1 tires: details and technical data | Pirelli"](https://www.pirelli.com/tires/en-us/motorsport/f1/tires). *www.pirelli.com*. Retrieved 2021-12-02. 1. **[^](#cite_ref-3)** ["Our story"](https://www.uniroyal-tyres.com/about/history/). *www.uniroyal-tyres.com*. Retrieved 2023-11-21. 1. **[^](#cite_ref-4)** ["Uniroyal"](https://www.uniroyal-tyres.com/gb/en/car/why-uniroyal/). *Uniroyal Tyres*. Retrieved 2023-11-21. 1. **[^](#cite_ref-5)** ["The advanced Shark Skin Technology for maximum aquaplaning safety | Uniroyal"](https://www.uniroyal-tyres.com/gb/en/car/service-knowledge/advanced-shark-skin-technology/). *www.uniroyal-tyres.com*. Retrieved 2023-11-21. v t e Tires Types Tubeless tire Radial tire Low rolling resistance tire Run-flat tire Michelin PAX System Airless tire Tweel Rain tyre Snow tire All-terrain tire Bar grip Knobby tire Large tire Mud-terrain tire Paddle tire Orange oil tires Whitewall tire Aircraft tire Tundra tire Bicycle tire Tubular tire Lego tire Motorcycle tyre Tractor tire Racing slick Formula One tyres Spare tire Continental tire Components Bead Beadlock Tread Siping (rubber) Valve stem Dunlop valve Presta valve Schrader valve Attributes Camber thrust Circle of forces Cold inflation pressure Contact patch Cornering force Ground pressure Pacejka's Magic Formula Pneumatic trail Relaxation length Rolling resistance Self aligning torque Slip angle Steering ratio Tire balance Tire load sensitivity Tire uniformity Lateral Force Variation Radial Force Variation Traction (engineering) Treadwear rating Behaviors Aquaplaning Groove wander Slip (vehicle dynamics) Tramlining Maintenance Tire maintenance Tire rotation Bicycle pump Central Tire Inflation System Tire mousse Tire-pressure monitoring system Tire-pressure gauge Direct TPMS Bead breaker Tire changer Tire manipulator Tire iron Life cycle Tire manufacturing List of tire companies Retread Waste tires Tire recycling Tire fire Blowout Flat tire Ozone cracking Organizations European Tyre and Rim Technical Organisation Tire Society Tire Science and Technology Identification Tire code ISO 5775 (Bike tire sizings) Plus sizing Tire label Uniform Tire Quality Grading (UTQG) Outline of tires Category --- Adapted from the Wikipedia article [Rain tyre](https://en.wikipedia.org/wiki/Rain_tyre) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Rain_tyre?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.