While i personally feel that this is merely a conservative suggestion that people consider that tires' lives are finite in time, even with light mileage, and while i feel that one can easily test (or have them tested), i went and did a little research on who's actually saying what. I'd seen the warnings, but too long ago to quote the "whom"
the summary is:
• Vehicle Manufacturers Recommend Replacement at 6 Years
• Tire Manufacturers' Warranties Expire at 6 Years
• Tire Manufacturers Recommend Replacement at 10 Years
• Industry Experts Recommend Replacement at 10 Years
You can find one summary of this issue here:
Discount Tire's summaryNHTSA is currently studying the issues (e.g.: no US Gummit or official industry rulings so far)
But the British ruber manufacturers have taken a stand, and is the source of the 6 year rule:
"The British Rubber Manufacturers Association (BRMA) recommended practice issued June, 2001, states "BRMA members strongly recommend that unused tyres should not be put into service if they are over six years old and that all tyres should be replaced ten years from the date of their manufacture." (source: Tirerack.com; MOT)
The Wall Street Journal (surprisingly, not Dan Neil) notes:
"A: I wouldn't replace the tires yet. While I'm aware of the six-year rule, I have also heard that 10 years is the lifespan of a set of tires. Tires degrade with time and exposure to sunlight and other elements. Still, I think six years is a conservative estimate.
The Rubber Manufacturers Association, a tire trade group, says it knows of no data that conclusively link a tire's age with serviceability." (emphasis added)
So, i conclude:
1. there is no hard and fast rule
2. there is an age limit to tires based purely on time
3. it varies greatly based on storage conditions
4. it has little or nothing to do with being high performance, except that we crash at higher rates of speed than others do
Grant
Grant
gee-lenahan-at-gee-mail-dot-com