Aged Tires: a Driving Hazard?

[paulccullen]

I found a good description of tire date stamps at Tire Expiration Dates

The date of manufacture is indicated by the last group of digits in the DOT manufacture code on the sidewall of the tire. The number is often stamped in a recessed rectangle. The DOT code tells who manufactured the tire, where it was made and when. The last group of digits in the code is the date code that tells when the tire was made.

Before 2000, the date code had three digits. Since 2000, it has had four. The first two digits are the week of the year (01 = the first week of January). The third digit (for tires made before 2000) is the year (1 = 1991). For most tires made after 2000, the third and fourth digits are the year (04 = 2004).

[patsparks]

Seriously people, if a tyre has cracks or is distorting or delaminating change the bloody thing before it kills someone but the age of the tyre shouldn't be an issue if tyres are inspected and maintained properly. Cracks in sidewalls occur due to exposure to sun wind and rain, none of these are issues in a resellers store room normally. De-lamination is a manufacturer defect or caused by bad road surfaces or air finding its way between the layers, this only happens when the tyre is in use.

Warning signs

Regardless of their age tyres should be replaced if they show significant crazing or cracking in the tread grooves or sidewall (Figure 3&4) and or bulging of the tread face or sidewall. All tyres, especially unused spare tyres, should be inspected periodically to determine their suitability for service. If there is any question about a tyre's suitability please consult your local Bridgestone Tyre Centre expert.

Sidewall cracks and

cracks in the tread are bad

In this image you can see the tread is bulging near the guy's thumb,
replace a tyre like this now, it will often make a noise.

[zenMachine]

Originally Posted by Rokeby

By chance, did you notice at the end of the video, when the news crew is being sold old tires, the car they are driving is a ... Prius?

Yup. I had to back up the video at that point to doublecheck to be sure before posting it in a Prius forum!

Patsparks, sensationalism is the state of journalism in the US, it's geting especially more so since the advent of Fox News. Nonetheless, the issue seems pretty serious. How do you explain the UK's law against selling tyres over six years old? (To be honest, I didn't even know that tyres had such a code to begin with.)

I definitely will do more research on this, and for sure will check my brand new OEM tyres that just got put on by the dealer last week.

[zenMachine]

Just checked all four tires. The Expiration Date is stamped on the outside, so no need to crawl under the car. Two of them say 1408, the other two say 1708. I'm quite relieved.

[Ct. Ken V]

Hi, all,

I just checked all 4 of my "new" tires that I just bought this May. Two of them are stamped with 1606, one says 1706, but I can't find any datecode after the mfr's # on the 4th tire. I guess I'll have to crawl under my car for that one (unless the inside of that tire is miss'g the datecode too). So mine were 2 years old already when I bought them, but they'll probably be worn out by the time they get to be 6 years old.

By the way, zen, that's the date of manufacture, NOT the expiration date.

Ken (in Bolton,Ct)

[dwreed3rd]

Originally Posted by Ct. Ken V

Hi, all,

I just checked all 4 of my "new" tires that I just bought this May. Two of them are stamped with 1606, one says 1706, but I can't find any datecode after the mfr's # on the 4th tire. I guess I'll have to crawl under my car for that one (unless the inside of that tire is miss'g the datecode too). So mine were 2 years old already when I bought them, but they'll probably be worn out by the time they get to be 6 years old.

By the way, zen, that's the date of manufacture, NOT the expiration date.

Ken (in Bolton,Ct)

I got the feeling up to 6 years old was O.K. to buy, although you'd probably want to keep an eye on them if running them on a low annual mileage vehicle, I.E. planning to use them for another 6 years. My understanding was that you should avoid buying tires older the 6 years. Not that 6 years is hard set, just a guideline. Personnally I'll probably try to find them in within a 2 year range, not necessarily knowing under what conditions they were stored. Dry, hot weather conditions will age them more quickly than in I cool, humidity controlled environment, whether in storage or on the car.

[pdhenry]

I bought my Miata's tires 10 years ago. It's been garaged 99% and only about 20K miles since then, but I guess I ought to be shopping for new rubber soon.

[dwreed3rd]

Originally Posted by pdhenry

I bought my Miata's tires 10 years ago. It's been garaged 99% and only about 20K miles since then, but I guess I ought to be shopping for new rubber soon.

How do they look? Is there any signs of dry rot or cracking like in the earlier post photo's? If they they look good, just keep an eye on them and avoid any long high speed trips without checking thier condition.

[pdhenry]

They look great, which I thought was fine. But the video implies that even "new" tires that have been out of the sun are dangerous if they are too old and have "dried out."

I'll have to give them a closer look, though. I figured that UV exposure was the main threat and they haven't had muich of that.

[zenMachine]

What consumers need is a way to test or measure these 'aged' tires for their roadworthiness.