The Winter Sottozero is Pirelli's "dual-season" Performance Winter / Snow tire developed to be effective as ambient temperatures approach freezing and below from mid-autumn until early spring by offering hot performance compared to summer tires when driven on cold, dry, wet or icy surfaces. Winter Sottozero tires are for the drivers of high performance sport cars, coupes and sedans who don't let their enthusiasm for driving cool off in winter.Winter Sottozero tires utilize a cap and base tread compound technology that combines two different compounds. The upper strata (cap) that comes into contact with the road surface uses Pirelli's latest generation silanes to bind the silica and polymer to provide greater stability during hard driving in both wet and dry conditions. The sub-strata in contact with the casing (base) uses nano-composites (aluminum silicates) dispersed throughout the polymer to provide the stiffness that enhances stability and driving precision. The tread compound is molded into an asymmetric tread pattern divided into distinct outboard and inboard elements to blend drivability on dry and wet roads with traction in light snow and on ice. High-density siping provides more biting edges to increase snow traction, ride comfort and noise quality. The tire's internal structure features Pirelli's ultra high performance tire construction to offer levels of performance not normally associated with winter / snow tires.Winter Sottozero winter / snow tires meet the industry's severe snow service requirements and are branded with the three-peak mountain snowflake (3PMSF) symbol.Install Pirelli Winter Sottozero tires insets of four only.Due to the traction capabilities of the Winter Sottozero tires, Pirelli recommends using Winter Sottozero tires only in sets of four to provide the best handling characteristics and tire performance. Related Information: What is the three-peak mountain snowflake symbol (3PMSF)?