I bought a 1998 car with Blizzak WS-15. I do not think that the tires were rotated/replaced. Front tires were more worn than rear so last summer I switched the front tires to the rear. Car has 78k miles now. I am thinking of getting new sets of tires, Goodyear Triple-Tread, and also increasing my tire size to 15". My question is, does anyone know the mileage rating for the Blizzak WS-15? I can't seem to find it on the net. Also should I ride the tires until the front tires are as worn as the rear tires? If I am over the mileage category of the Blizzak, I will not hesitate to purchase new sets of tires.