all of a sudden i have a big vibration in the steering wheel and car is pulling to the left. it feels like i'm riding on a flat tire but it is properly inflated. these are the stock contis on front that have 50000 miles. I've already ordered new Hankook Evo's so i will know for sure in a few days if it is the tire. Dont plan on driving it until then. Any other ideas what it could be?