How long can tires be stored before they get hard?

[RSwannabe]

I run Bridgestone S-03's on my 911 and love them. Needless to say I was very disappointred when they discontinued them. The choices of performance tires for 15" wheels are getting slimmer and slimmer. This being the case I was thinking of stockpiling a set or two of S-03's for future use. My question is this, how long can a new tire be stored before it starts to get hard and crack or no longer be as good? Does anyone have any experience with this?

Thanks in advance.

[boxster03]

I ordered five new tires, three came from the warehouse with a mfg. date that was about 6 mos old and they of course were fine. two others came with a mfg. date that was over 2 yrs old and you could tell a huge difference in the tires. the older tires were much harder and my installer did not want to mount them. they were sent back and after a few words with the warehouse they found some newer ones.

don't think tires that have been on a car for 2 or 3 yrs are an issue but those that sit around in storage are a different story. I have heard people say that the shelf life of a tire might be around 5 to 6 yrs but even after half that amount of time you could see a difference.

[Gearbox]

I'm not sure if you can find anyone on this board to give you a precise answer since it would involve a complete knowledge of the compound ingredients and a chemist to determine the interactions over time. But as for storage, I keep my race tires over the winter in a thick plastic bag, pickeled in a solution called Formula V that is suppose to "feed" the tire and keep them soft, and I suck most of the air out of the bag with a shopvac before sealing them up. Also keeping them in the coolest place possible. like your basement away from any light, is also highly recommended. The longest I kept tires stored for was two years and the durometer readings were the same as the day I stored them. I was using Hoosier Slicks at a 430 coumpound which is just about as hard as high performance street tires. If the sets are are going on clearence, and if they are cheap enough, go for it.

[boxster03]

but what about your pyrometer readings