<VV> Old tires

[Grant Young]

Just read in the AAA travel magazine that the safe life on tires, regardless of mileage, is about 6 years. Seems the loss of ozone has not lessened its ability to deteriorate rubber. Article says that the effects can not always been seen. My daughter has some personal experience with some 10-12 year old SUV tires. Two of them came apart on two different occassions, so she replaced them (not Firestones and with more than half the tread life) before the other two failed. I guess that also means we should be wary of using our regular spare tires which are usually stored for many years? 
Grant