The Pilot Alpin PA4 N-Spec is Michelin's Performance Winter / Snow tire developed to meet the needs of Porsche enthusiasts who may encounter snow-covered roads when they drive their sports cars year-round. In addition to utilizing eco-focused manufacturing methods and enhancing vehicle fuel economy through low rolling resistance, as designated by Michelin's Green X* branding, Pilot Alpin PA4 N-Spec tires are designed to deliver secure driving year after year in cold, wet and wintry conditions.Pilot Alpin PA4 N-Spec tires feature a full silica-based, sunflower oil-enriched Helio Compound+ tread rubber that remains more flexible in low temperatures for better traction in cold conditions. This compound is molded into a directional tread design that features a heavily grooved tread pattern, Michelin's high-density Stabiligrip 3D sipe technology and wrap-around shoulder designs to enhance acceleration, braking and handling.The tire's internal structure includes twin steel belts reinforced by Michelin's FAZ technology that places spirally wound filaments of polyester cord under the tread to combine stable feel, confident handling and high-speed capability with ride comfort.Pilot Alpin PA4 N-Spec winter radials meet the industry's severe snow service requirements and are branded with the three-peak mountain snowflake (3PMSF) symbol.Note: Snow platform indicators (the equivalent of "snow wear bars") are molded into the Pilot Alpin PA4 N-Spec's tread grooves to inform the driver when ice and snow traction will be reduced as the tire's tread reaches the point where the remaining tread depth becomes less effective in deep snow.Install Pilot Alpin PA4 N-Spec tires in sets of four only.Vehicles should always be equipped with equivalent tires at all wheel positions. These winter / snow tires, due to their exceptional snow and ice traction provided by their unique tread compounds, must be used in sets of four to help ensure proper vehicle control. Mixing asymmetric and directional tires is not permitted.*Specific sizes featuring Green X technology are identified as such on the Sizes tab, as well as on the tire's Specs tab. Related Information: Green X Technology | What is the three-peak mountain snowflake symbol (3PMSF)?