Bias Ply Age?

A couple years ago, on the news, I listened to a story about how its possible to receive a set of new,radial tires that have been waiting on the shelf for some time. In some cases 6+ year old tires were being mounted. I know that radial age can be determined by a marking code on the tire.

For Reproduction Bias Ply tires is it easy to determine the age. Does any one check age on their..cokers?. Any one have any links to information about this. What is a safe shelf life for a bias ply tire? 4-5 years?

 

I don't have a Coker to read the numbers off of but I'm pretty sure it is a requirement for all manufacturers to code their tires. The cut off date for selling a bad tire is 7 years and it's due to the rubber compound breaking down and I would believe it doesn't matter if they are radial or bias ply.

 

From wikipedia,

DOT code
In the United States, the DOT Code is an alphanumeric character sequence molded into the sidewall of the tire for purposes of tire identification. The DOT Code is mandated by the U.S. Department of Transportation. The DOT Code is useful in identifying tires in a product recall.
The DOT Code begins with the letters "DOT" followed by a plant code (two numbers or letters) that identifies where it was manufactured. The last four numbers represent the week and year the tire was built. A three-digit code was used for tires manufactured before 2000. For example, 178 means it was manufactured in the 17th week of 8th year of the decade. In this case it means 1988. For tires manufactured in the 1990s, the same code holds true, but there is a little triangle (&#916 after the DOT code. Thus, a tire manufactured in the 17th week of 1998 would have the code 178Δ. In 2000, the code was switched to a 4-digit code. Same rules apply, so for example, 3003 means the tire was manufactured in the 30th week of 2003.
Other numbers are marketing codes used at the manufacturer's discretion.

 

good info when buying tires---but you still need to check older tires for signs of breakdown --cracks , separation, etc...

 

So whats the problem of using a radial that sat on a warehouse for ten years?
Theres people using old crossplies with 30, 40,or even 50 years of age.

 

and that's a really, really bad idea.

 

When I swapped my bias plies for radials recently, the guy at the tire shop was curious as to how old they were and tried to look them up but could not find any numbers he recognized. He had to call his supplier and ask... they told him that date codes were not required until the 1970's, only a DOT ID number that specifies the manufacturer. I'm not sure if mine were original Firestones or repop Cokers, but there was no way to date them other than they looked old as shit. I'm thinking that if the originals did not have date codes and the Cokers use the same mold, then they probably don't either.

 

When I was a Kid in the early 60s I remember seeing new tire's wrapped in paper.Why did they do that? And why did they stop?

 

I think this was done to keep Whitewalls clean. If a blackwall leans on a whitewall, the whitewall might get dark/brown/yellow spots.

Today no whitewalls are used, therefore no need for it on new tires.

 

It sure wouldn't be ME running tires that old.

When tires come from Coker they are wrapped in clear plastic that is like 2 inches wide and it goes around and around the tire. You have to cut it off when you get them.
Don

 

The state of Maryland is in the process of passing a new law that you can't sell a tire thats older then 2 years old (off DOT code) Many other states are looking into something like this. If you ever purchase a tire from Kelsey tire(Goodyear's) they always come wrapped in plastic, it's more to protect the tire and wide white wall.

 

All rubber ages over time, regardless of usage. That is basic chemistry. Using a set of unknown age, or known to be old is basic something else entirely. Science denial can have unfortunate results.

 

haha, yeah i know. I never said it was a good idea but theres a lot of guys using old bias tires and it seems that as long as they are in good condition, not dry, with good thread etc... it seems they not having problems. 520s and lowlows come to mind.

If radials are stored in a warehouse for a few years, kept out of direct sunlight, excessive humidity etc.. i dont think theres any serious risk using them.
After all i think some of our classic cars roll on the same set of tires for many years, specially weekend drivers, or everybody swap them for new ones after 4 years even if they have half of their thread still?

PS, im NOT tryin to be a smart ass

 

Don't know why they wrapped them but it made them a bitch to mount. The paper kept the sidewalls close together even after the paper was removed which made seating the bead a pain during the mounting process.

 

They also wrapped old bicycle and motorcycle tires around that same time. No whitewalls.

 

Thought this might be some help.

http://www.goodyearrvtires.com/tire-storage.aspx

I remembered the electric motor-ozone link and while looking it up found the above. Hope it is some help.