Tire date codes and shelf life/expiration date

I recently read an article about date codes on tires and finite usable life. I guess the manufacturers are not happy since the tires would be deemed "unusable" after a certain timeframe. Some of the OEM manufacturers say 6 years while Michelin says 10 years.

We all know that the rubber compound changes due to temperature, pollutants and age. What I want to know is how is "life" determined if there is so many variables? Also, if distributors have to basically throw away tires after 6 years, how do think that will affect the enthusiast community? Manufacturers will be hesitant to make tire sizes that don't sell (AKA 14" and 15" performance tires) and instead focus on more mainstream sizes.

What do you GRMers say?

I find it hard to believe Michelin says 10 years, because the last several sets I've had wouldn't make it 5 without cracking. But I do have a set of Michelin XZXs on my Sptifre that are over 20 years old and look great. The car is parked inside the garage 99.9% of the time so sunlight doesn't hit them. I doubt these tires have 2,000 miles on them.

What kills tires is heat and UV rays i.e. the sun.

I had a set of tires on my van that the PO put on. The production date was something like 2000 or 1999. The tires did not have many miles on them as the van sees only 1-2K miles a year. The van sits outside but is not in the sun all that much due to objects blocking the sun from the tires. Finally late last year one of the rear tires suffered a tread separation and I was forced to use the spare tire which was even older, I'm still not sure when it was made. I got home OK and then went shopping for new tires.

I do think that no store should be allowed to sell tires older then 4-5 years old as "new" seeing that some car owners may not drive that much and you could end up with 12-15 year old that can fail suddenly. I was lucky as it was a rear tire that let go, it may not have been pretty if it was a front one. I do have to say that I did know that my tires were old and I did plan on getting new ones but just kept putting it off.

Maybe auto manufacturers are more conservative after the whole Firestone thing.

jimbbski wrote: What kills tires is heat and UV rays i.e. the sun.

+freezing weather … as far as race and ultra high performance tires are concerned

Does this mean I need new tires? Hoosier drag radials purchased 2005, stored in an unheated garage that saw single-digit temps this winter. Car traps around 105.

I would talk with a Hoosier engineer …

In reply to wbjones:

Oh, no! I don't want to do that! I know exactly what he'd say!

New unused tires still covered in mold release in a tire warehouse are good for years. The clock starts ticking when you start using them.