As the report is so chilly I copied some parts out of the text to give a short impression of the seriousness of the subject.
.....
"What can be learned from these cases? First, it is apparent that (old f.e. spares GW) tires with
acceptable tread and no significant visible signs of defect or degradation are likely to find
their way into service or continue to remain in service regardless of their age.
.....
Following is the language from Volkswagen’s manuals:
WARNING - Old tires can fail in use, causing loss of vehicle control and personal
injury. Replace tires after six years regardless of tread wear. Always reduce
speed and drive cautiously if you must use an old tire in an emergency. Replace
the tire as soon as possible.
.....
Toyota’s warnings contain the following language:
Any tires which are over 6 years old must be checked by a qualified technician
even if damage is not obvious. Tires deteriorate with age even if they have never
or seldom been used. This also applies to the spare tire and tires stored for future
use.
....
ADAC responded to approximately 40,000 tire breakdowns in 1985, 90% of which took place on
the autobahn. From the tire-related breakdowns, the data from 5,000 reports were usable
for this study and included the DOT number. Based on a correlation of tire registrations
with the number of tires by age, the author concluded that failure frequency rose
disproportionately with increasing tire age and estimated the probability of a breakdown
from a tire was eight times as high with a nine-year-old tire than with a two-year-old tire.
....
Tire Engineering Policy Committee (TEPC) meetings in late 2003, chaired by a Bridgestone representative and attended by representatives of Continental, Cooper, Goodyear, Michelin, and Pirelli, in which they decided to draft recommendation for maximum service life for light truck and passenger tires. The recommendation noted 'While most tires will need replacement before 10 years, it is recommended that any tires in service older than 10 years from the date of manufacture be replaced with new tires as a simple precaution (including spare tires), even if such tires appear serviceable (or even if such tires have not reached the legal wear limit'.
This recommendation applies also to retreaded light vehicles tires (passenger and LT tires through load range E) older than 10 years from the date of manufacture of the initial casing.
For tires that were on an original equipment vehicle (i.e., acquired by the consumer on a new vehicle), follow the OE vehicle manufacturer’s tire replacement recommendations.
....
Gerard Wuisman
1970 280sl
