<VV> Tire Dates / Life / Age etc...

[Eric Prosise]

Maybe I should start by saying that my previous job was a Quality Engineer 
for a major Agricultural Tire company, that also produced passenger tires at 
other factories....I figure I may weigh in on the tire age / date code 
issues.
DOT requirements for passenger tires state that the tire must have 4 digits 
which will allow the tire to be traced back to the week of manufacture.  I 
think passenger tires may actually have gone to 5 digits to allow for the 
day of the week (1-7), so basically, 10101 would be a tire produced on the 
first day of the first week (full week) of 2001.


I dont really want to bore everyone with what age and conditions can do to 
tires.  There are so many variables....it would take forever.  I have over 
70,000 miles on my current set of Goodyears on my truck (a 55k mile tire), 
and they look sad.  They still have tread left, but the ozone checking is 
getting to the point that the tires may not last much longer.  Older tires 
usually have flat spots bias or radial, hardening of the shoulders of the 
tire, cupping if left under inflated, sidewall separations of within the 
plies of the tire, cords can become brittle (nylon / polyester), the white 
sidewall rubber and black sidewall rubber can develop separations between 
the two (which happened on an original tire from my '64 Greenbrier, peeled 
the white sidewall right out)....  I check date codes when I buy tires, new 
or used, and I also inspect tires that I have put on my vehicles.  Most tire 
repairs, the untrained eye will not catch, and most will have no impact (its 
amazing how little NHTSA allows you to repair), but I would rather have a 
pristine tire for the price I pay.  I can also tell you that Firestone, 
Goodyear, and Michelin tires all age differently, and some hold up to 
certain things better then others.

I dont know if I really added anything to the discussion, but hopefully 
provided something to think about...

Eric
'66 and '63 Monza, new tires on both, and a "couple" extra sets laying 
around.

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