I drive a 2009 Mazda 3 Sport. I live on top of a hill where the road is not gritted by the council due to local cuts. When it snows like it did recently we could not use our car for a few days until the snow melted, and this is why I am thinking of winter tyres. At present the tyres on the car are Bridgestone RE 040XZ89V (17-inch rims). Would a smaller tyre fit the wheels or would I have to buy new wheels to replace my present ones? What make of tyres would you advise and from what month is it advisable to use winter tyres?