How old can tires be before you should replace them?

Look for hair line cracks, up close to the rim, going around the rim.

Sometime these can be indications of a tire going bad

I bought some summer tires in 1997 for my old Jeep Wagoneer, but I also had winter tires for it. so I would change them out twice a year, depending on the season.

The last couple of years, I left the summer tires off, since I didn't drive the Jeep much in summer...and just kept the winter tires on it.

I gave my son my summer tires, a few months ago. 15 years old...and no sign of dry rot, no cracks....amazing. So he is using them. I did warn him about old tires, over 6 years old...should be tossed, but he wanted to use them.

And my Jeep pickup, also had new tires on it, in 2004... four years later, they show signs of cracking around near the rim. They are still on my truck, but I do not drive far. Tires treads are almost new, but I put maybe 300 miles a year on the old beater. Jeep pickup...when was the last time you saw one of those?

The point is... the 15 year old tires looked much better then the now 8 year old tires. So who knows? Maybe the rubber was just better on the Wagoneer tires, then on the J20 truck.

Old tires need to be checked for tread separation and dry rot. If either of those is present, throw the tires out.

A lot depends on how they were stored.

I know that for trailers that sit outside, exposed to sun and ozone, they recommend replacing the tires every five years, regardless of tread wear. The rubber just falls apart.

If your tires have been in a nice, dark basement, the rubber may not have deteriorated much. You need somebody to inspect them and give you a professional opinion.

Michelin recommend tires be taken out of service after 10 years.

you need to check them ! even though there are a lot of tread they still can be dry rotted.