One thing to watch for with old or underinflated tires is what truck tire techs call a 'zipper failure' (I think) - where the tire suffers a traumatic failure along the sidewall when it is being inflated.

Of course, truck tires use higher pressures, but I think that car tires can be dangerous as well.

It depends entirely on where you live.
If you live in a cool climate, you *may* get away with running on old tires for a very long time without any issues what so ever, but if you live in the kind of super hot climate I do it is seriously not advisable ( we had 106 today in the shade... 121 in the sun before the heat index. You dont even want to know what the full heat index calculation is for that with 58$ humidity , driving a car in that is pure torture on a vehicle) around here tires generally give out due to age long before they ever run out of tread, so it is up to you to make a judgement call.

Even with the best tires I always have cases start blowing in sets, always with tons of tread left When I lived up north, we could run tires from the dark ages and they would last forever even running bald.
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-------Robert,:'00 XC70. '95 960, '93 940t, '90 240 wagon, '94 940SE, '84 240 diesel (she's sick) , '80 245 diesel, '86 740 GLE turbo diesel, '92 Ford F350 diesel dually

My only reservation on older tires.. they do naturally dry out.
They get a bit hard and lose some of their wet traction. As far as falling apart ... No, I would not worry in the least.

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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.lyse.net/brox/TonyPage4.html http://cleanflametrap.com/tony/

My grandfather had a blow out in a 7 or 8 year old car that only had 25,000 or so miles on the factory tires. Plenty of tread but they were at the end of their useful life.

I would have no problem whatsoever with the 6-year-old Michelins, if they are truly NOS, i.e. stored out of the sunlight and preferably away from other ozone-producing devices such as large electric motors or welders.

You realize, of course, that all tires built since back in the 70's have a "born on" date encoded in the sidewall, right? For instance, if you see...

DOT CX9F *8733210*

...on the sidewall, the last four digits indicate the tire was manufactured 32nd week of 2010 (3210). If your XZX's are truly only 6 years old, the last two digits should be 07.

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Gary L - 142E ITB race car, 73 1800ES
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