Slick tyres

A racing slick (also known as a "slick tyre") is a type of tyre that has a smooth tread used mostly in auto racing. The first production "slick tyre" was developed by M&H Tires in the early 1950s for use in drag racing. By eliminating any grooves cut into the tread, such tyres provide the largest possible contact patch to the road, and maximize traction for any given tyre dimension. Slick tyres are used on road or oval track racing, where steering and braking require maximum traction from each wheel, but are typically used on only the driven (powered) wheels in drag racing, where the only concern is maximum traction to put power to the ground.

Slick tyres are not suitable for use on common road vehicles, which must be able to operate in all weather conditions. They are used in auto racing where competitors can choose different tyres based on the weather conditions and can often change tyres during a race. Slick tyres provide far more traction than grooved tyres on dry roads, due to their greater contact area but typically have far less traction than grooved tyres under wet conditions. Wet roads severely diminish the traction because of aquaplaning due to water trapped between the tyre contact area and the road surface. Grooved tyres are designed to remove water from the contact area through the grooves, thereby maintaining traction even in wet conditions.

Since there is no tread pattern, slick tyre tread does not deform much under load. The reduced deformation allows the tyre to be constructed of softer compounds without excessive overheating and blistering. Modern day slick tyres have now developed particular performance qualities in a specific window of temperatures, becoming "sticky" when accumulating enough heat, and thus give much greater adhesion to the road surface, but it also has a lower treadwear rating; i.e. it wears out much more quickly than the harder rubber tyres used for driving on the streets. It is not uncommon for drivers in some auto sports to wear out multiple sets of tyres during a single day's driving.

In Formula One, slick tyres were not used from the 1998 to 2008 seasons. Dry weather tyres with mandatory circumferential grooves intended to reduce total grip and reduce cornering speeds were used, and were still often referred to as "slicks" as the grooves were not intended to disperse water and could not be used effectively in wet conditions. Slick tyres were reintroduced from the 2009 season.

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