Tire Age
 

I've got 2012 Kumho's on my '98 Boxster and they still have at least 80% tread left. I know rubber degradation is a real issue, but there's no indication that's occurring, at least outwardly. What's the danger of driving in the city (under 45mph) with these tires? I do plan to replace them, but don't want to chance a failure that might damage the cars body.

Usually tire degradation is caused by the Sun's UV. If the car has been stored inside and, like you already mentioned, they show no signs of degradation, you should be fine. But really, it depends on your comfort level and driving. I wouldn't go on the highway with them. When you start seeing hairline cracks on the sidewalls, then you're seriously risking a blowout.

Edit: I just noticed you're in FL. Maybe you should get them changed. Sea air and heat also contribute to degradation.

I would be cautious with any tire more than ten years old, regardless of how it has been stored.

We recently had a customer with Continental tires just over 15 years old with 65-75% tread left on a car that is stored in an environmentally controlled and totally dark garage and rarely used. We recomened he change out the tires due to age during a state inspection, which he did for some new Michelins. One of my techs took the two rear tire take offs to run on his track car because they were in such good shape. About two and half laps in, both of the take offs failed, both throwing off their treads.

Age matters in tires.

True, but tracking is a whole different animal than city driving at 45 MPH. I did a PCA event and we had to make sure our tires were 3 years old or newer.

The state inspection authority has been discussing setting an 8 year time limit for tire age regardless of tread depth on all cars as part of the annual inspection cycle, and multiple Porsche dealers in the area that offer free state inspection to any Porsche owner have already set a max age of 10 years for the tires.

Formal tire age limits are coming...............

Thanks guys....I'll get them replaced soon. The car has been garage stored with a cover, but my motorcycle has been in climate controlled storage its entire life, and rubber stuff definitely deteriorates even in ideal conditions.