hi all thought i would add a little to this topic, having tried a couple of different brands of winter tyres i can say with out doubt they work and make a real difference as long as its colder than about 7c . winter tyres are not softer compounds they are actually harder according to michelin and vrederstien at least ,they have little cuts in the tread blocks which act as little claws this is what gives them the grip and because of these little cuts(sipes) the tyre generates friction which creates heat which is why they use harder compounds. in the case of michelin alpin 3s these cuts(sipes) only run to 4mm in depth so when the tyre is half worn it becomes a summer tyre albeit not quite as good as a dedicated summer tyre ,having looked at the khumo kw23 that too has most sipes cut only 4mm into the tread suggesting the also would become less effective as a winter tyre when half worn. :)
