One thing to consider is if the tires were mounted and sitting with the weight of the car on them for that long. I bought my '84 Crown Vic from the proverbial little old lady. The car had sat for four years before I found it, she had just put brand new Michelins on it, drove it home and parked it for the four years. Even the little rubber nubs were on the tires yet. Entire car only had 50,000 miles on it.

However, when I got the car running after it's long rest it drove like the tires were made of bricks! It hopped all over the place and even shook stuff off of the dashboard. Evidently the tires had taken a set and had flat spots on the bottom. I kept driving it, hoping they would round out, but they never did. 3 months later I had new ones put on and the problem went away. The tire shop told me once they take a set they are done.

Just so you might consider that.

Don