I recently replaced the tires on my 1990 coupe. I inherited from my dad, and he owned it for 3 years starting back in 2008. I never knew how old the tires were, but the tread was very good (like new), but I always felt the ride was very unforgiving. Felt every pebble like you drove over a brick. I noticed the front tire in the garage the other day looked low, so I got down to inspect it closely since the side wall had a slight bow due to the low pressure. I saw spider web style cracks in the side wall where it was bowed. I then set out to learn how to read the date code on the tires. Date code was 324, and eventually figured out that this 3-digit style code was pre-2000 and meant the tires were manufactured in the 34th week of 1994. Yikes. I have been driving on 24 year old tires! So new tires here I come! Ride is much better now, and very glad nothing ever happened with such old tires on the car.