From what I've read, they work perfectly fine in the dry, so long as it's cold. The reason being is the silica rubber compound used in them is softer than that of normal summer tyres, meaning they stay more supple, and thus more grip, in lower temps (ie, under 7 deg). So they'll be fine to run on dry roads over winter, but just change back to summer/normal tyres when the temp begins to warm up, and definitely before it gets to 7deg (to avoid premature wear)