I'm trying to determine how old the tires are on a new (to me) 1973 coupe that I purchased. They don't seem to have the usual 'wwyy' format after the DOT info on the sidewall. They're Dunlop GT Qualifier tires. I've looked all over the net, and can't seem to find anything referring to this tire's codes. Here's a picture of the DOT info:

Any ideas?

 

If you cant find any info online, try looking at the other side of the tires, sometimes they will have an obvious date code there.

 

Check the inner sidewall for the entire Tire Identification Number which will have the date code.

 

Nice photo...never paid attention to a Dunlop date code. Here is a brief history of the tire date codes. The link (below) is an article written on Corvette tire safety, history of the date codes and lots of nice photos but limited to Good Year tires.

Those first date codes used in the 1970s were week/year format but this was the format Good Year used. A complaint by tire safety advocates (1970s -80s) was that each manufacturer could use their own format for tire date code and I suspect that's what we may have with the Dunlop. The Federal DOT required codes beginning in 1971 but there was some overlap before tires showed up on vehicles with date codes. Your 73 may well have an early Dunlop tire less a standardized date code.

It wasn't until 2000 that the date code was standardized as you record above and that date code had to be embossed on both the inboard and outboard side. Before 2000, manufacturers only embossed on the inboard side as noted above.

If I were to speculate, I would say that the date code on your Dunlop is the 24R and could represent a week/year (2nd week of 1974 or even 84) or the 24th week of some code with R the year code.

Corvette Tire Safety

Hope this helps!

 

I personally would replace the tires before driving the vehicle. In my opinion, although it difficult if not impossible to determine when a tire should be replaced due to age, if your tires are from 1973 or even 1984 I would not take the risk. Several years ago I bought an all original, including tires, 1982. Had to make a hour trip home so I made an appointment ahead of the pickup to get new tires. Barely made the one mile trip to the tire store because the tires began to separate.

 

Check inside on the blackwall side. It should still have 4 digits indicating week and year. As previously stated, plan on replacement. They are likely old.

 

I found out today the DOT date on the inside of the tires is showing 08/07. The tire guy said the side walls are in good shape and show no sign of dry rot or separation at the rim. For now, I'll keep them on the car and entertain replacing them in the Spring.
Thanks for all your inputs.

 

11 years old. It doesn't matter how good they look, they are not safe.

 

Hmmm...you should post a picture of the date code since our curiosity is up. The date code if a post-2000 formt, should be on the outboard side of the tire as well.

 

Roger that.
Thanks.

 

I'll get that picture posted when I get a chance.

Thanks.

 

Been a Costco tire manager for 11 years. We're not permitted to sell a tire with a build date of over 3 years, Michelin says if there's no major cracks in tread or sidewall, tires can be deemed safe up to 10 years after manufacture. They say after 10 years they should be removed. I've Talked to factory reps and was told that there are lubricants built into the rubber which work their way out as tire go round and age, and eventually those lubricants become exhausted. I don't bu any of it. The biggest killer of tires is the sun. I've seen countless tires with severe cracking on the outer sidewall, while the inner sidewalls are smooth and supple. I've seen unused spares in the trunks of 25 year old cars, that look and feel brand new. If a car is stored in a garage or under a cover, the tires age very slowly.

 

I'm with you on that one. As long as there`s no cracks and its not separated they will last for awhile. Tire manufactures love selling tires!

 

Put the rubber money saved into your insurance policy. That should balance things out...

 

Yes tire manufacturers love to sell tires, but there is a real danger from old tires. Rubber starts to decompose the minute it comes into contact with air (not just UV rays etc).

Your comment about "as long as there's no cracks and it's not separated they will last for awhile is very poor advice - period. Please read and learn the facts before you offer advice about something that could get someone seriously injured or worse.

There are places to save money for sure - tires and safety items are never a good place to cut corners.

 

AGREE!!!

 

I don't remember the thread but about a year ago or so someone posted pictures of the tire separation on their C3. They were at highway speed when it came apart and destroyed his fender. Perhaps someone may remember this. According to that poster his tires looked good. If you don't want to replace your tires now I would limit my driving to neighborhood streets and slow speed. I would not do much driving at highway speeds. The damage you can do to your car or yourself aren't worth it.

 

I'm sorry if I gave the impression that I'm deeming all old tires are safe. But I have managed a tire center for over 10 years that installs 300+ tires a week and have seen it all. I have a degree in engineering, and have been to tire factories, talked to reps and tire engineers a plenty. Tires are constructed of 5 basic parts. You have the inner liner, which serves as a tube. or to seal the tire from leaking air. You have the belt package, which is the the heart of the tire, with provides the structure and the gives the tire its strength and ride characteristics. The there is the bead, which is wound onto the belt package and holds the tire securely on the rim. Then you have the tread layers, which are bonded onto the belt package. Lastly, there is the outer rubber sidewall whose only job is to protect the belt package. A tread separation occurs when the tread layer separates from the belt package. This almost never happens due to a manufacturer's defect. It almost always occurs when air is allowed to enter between those layers, usually due to a puncture (not necessarily one that causes an air loss). Not to mention heat, which is the greatest cause of tire failure, usually due to over inflation, under inflation, over loading, or excessive speed. ( the speed rating of a tire is actually its ability to dissipate heat). Now, most of these things can occur to any tire, regardless of age. Any tire can fail, the chances are a little less on a newer tire. The important thing is to know how to handle a tire failure. No sudden movements, no sudden braking, keep the wheel straight, ease over to the right, and gently slow down. I could talk tires all day, but it's getting late.