A slick tyre is a type of tyre that has no tread pattern, used predominantly in auto racing. By having no tread pattern the tyre presents the largest possible contact patch to the road for any given tyre dimensions. Since there is no tread pattern, the rubber will not deform as much under load. This reduces the heat generated by deformation, and thus allows the tire to be constructed with a softer compound without the tire blistering or overheating (a phenomena most drivers will refer to in a manner such as "the tires were getting greasy"). Therefore, slick tyres provide far more traction than patterned tyres on dry roads. However, on wet roads, the traction of a slick tyre is severely diminished because it has no tread pattern to expel water from its contact patch. For this reason, they are not suitable for use on road vehicles, which must be able to operate in all weather conditions. They are used most widely in auto racing where competitors can choose to use different tyres based on the weather conditions and can often change tyres during a race. In Formula One, slick tyres are no longer allowed, yet dry weather tyres are often still referred to as 'slicks' as they have similar characteristics in wet weather.