We have a 2002 Mercedes C-240 with low mileage, so the tires do not show much wear. We live in Florida, though, and wonder if the tires deteriorate in hot weather and should be replaced anyway.
This is a fascinating topic. Thanks for bringing it up.
I remember reading not too long ago that there would soon be a sort of “expiration date” printed on the sidewall of each new tire, because tires DO degrade over time, even if they have limited mileage.
If I remember correctly, the agreed-upon time limit was seven years, so you have another year to go.
If you garage your car, I think you might be able to stretch this time limit, as UV damage from sun exposure was one of the main problems. A car in a garage is NOT exposed to UV radiation, nor are its tires.
This could, of course, be a plot to sell more tires when they are not needed.
Your current tires could be as much as 7 years old, which is getting a bit long of tooth (especially in a warm place like FL). Is there any cracking visible anywhere on the surface of the tires? Are they holding air pressure well? Has the car been kept garaged so that the tires have had little exposure to UV light (UV attacks rubber)? Have they been in a high ozone environment (ozone attacks rubber)? Even if you can give “good” answers to all, you may want to play it safe and change the tires anyway, given their age. For a car of that value, why skimp on rubber?
Take a look at the side of the tire and look for a small oval outline with 4 numbers inside of it. The numbers may say something like “0702”. This number is the date the tire was manufactured. The first two numbers are the week it was manufactured, and the next two numbers are the year. So in this example “0702” would mean that this tire was made in February of 2002.
In general after 6 years I would say it’s time to look at new tires because the rubber will have hardened some and performance will have diminshed. After 7 years it’s a sure thing that they should be replaced. You may not drive fast, but the day may come that you need to stomp on the brakes to avoid hitting a child who runs into the road.
I am going to go against the grain here and stir up some controversy.
Visible damage due to UV and ozone affects only the first few thousandths of an inch on the outside of the tire and has little to no impact on the structural integrity of the tire.
If they were retreads, I might be worried at this age, but for the tires that came on your Mercedes, I would not begin asking myself this question until they were twice this old, and then only if my wife or daughters were driving the car.
There was a recent documentary recently I guess on CBS or somewhere else. You can find it on youtube. It talks about US not stepping up and putting an expiration date on tires. They would go to Sears clearance and the tires being sold were 6 or seven years. They also reported a few accidents with “new” tires exploding. It was somewhat exaggerated but you get the point. You have to find out the date your tires were built, they might had been old by the time they made it to your rims. Rubber does deteriorate with time and has a “shelf life”. Same for timing belts and hoses.
There are big differences based on the conditions the tyres encounter. If you see any cracks on the sidewalls, then it is likely time to replace them now. Hot weather has a minor effect as I understand, but Ozone has a large effect, so a tyre in NYC would likely be aged a lot faster than they would in Florida.
If you are not sure, consider taking them to your local tyre center or mechanic and let them look them over. Remember the tyre center would have an interest in selling new tyres, so if they say they are OK, chances are they are OK.
I also agree with the others who are pointing out that the tyres may have been old when they went on, although that is not likely with a car you purchased new for the original tyres.