Pilot 4S are very specifically summer performance tires, very narrowly optimized for dry pavement with some wet pavement capacity and enough durability and compound flexibility to cover most conditions on mild climate areas. It is in no way designed to handle ice, snow, or dirt trails.
All-season rated tires is rather an arbitrary designation and it can very greatly from model to model and brands. Some are closer to summer performance tires and others are truly a compromise of everything to cover all things. Being a "jack of all trades" these All-Season tires cannot do any specific thing with very high capacity. It is moderately ok in all aspects.
Winter tires, like summer performance tires, are also very narrowly focused tires, which is designed to operate very specifically in a certain set of environments, in this case WINTER. The tire compound is designed to stay soft in extremely cold conditions, the tire surface is full of sipings and micro grooves to absorb and dissipate away water, and claw into ice. These winter tires typically have twice as much grip as All Seasons in ice, and 1.5 times more in snow.
Having said that, these tires cannot cope with high temperatures or very high speeds, and wear very fast in hot dry day or being abused in dry pavement.
So most people who can afford to get TWO sets of tires for different seasons will do well with Summer Performance tires in wider size wheels, and enjoy sporting grip and relatively high overall balance in dry and light rain. And in the winter months, switch to Winter tires to cover for the worst weather, and drive mildly in these months in exchange for superb protection in snow and ice, heavy rain etc.
For others who must stay within budget and have only resources for single set of tires, the All Season is a choice.
That is a set to cover all situations, without excelling in any one role.
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Moto Miwa