An update from a Wall Street Journal article yesterday (10 Nov 2005):
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(TITLE) Bridgestone's U.S. Unit Advises Tire Life-Span Limit

Bridgestone Corp.'s U.S. tire-making unit has broken ranks with the
rest of the U.S. rubber industry in recommending a maximum life span
for passenger and light-truck tires.

In a recent technical bulletin to its dealers, the tire maker said all
tires -- including spares -- that are more than 10 years old should be
replaced, regardless of their external appearance. The company cited
the same recommendation issued in September by the Japan Automotive
Tire Manufacturers Association. Bridgestone is based in Japan. [more]
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The article goes on to state that many U.S. car companies have begun
similar recommendations, though with shorter lives; e.g., Ford started
urging its customers this year to replace tires that were more than six
years old. The main U.S. tire industry trade group disagreed, saying
there was no evidence to support a maximum service life. Bridgestone
conceded it was not aware of any technical data to support a max
service life, but was going along with the Japan tire makers'
association's recommendation.

It's difficult to separate the impact of liability concerns from actual
risk. My trailer spare tire had been stored inside the trailer for
nearly 14 years before I used it on the way home from the New Castle
Regionals in Sep. Although it looks brand new, given the above (and a
recommendation by Sam Giltner--see his earlier posting), I probably
won't run the spare on the trailer next year. The only real question is
whether to throw it away or move it back inside the trailer again for
backup duty.

It probably makes sense to rotate the tires to cycle through the spare
to avoid this situation in the future. Anyone doing that?

Chip Bearden
ASW 24 "JB"