Hi folks, I also posted this in the C4 tech forum. It seems like a lot of people think their original & older tires are in good shape because they look great. Not true. Watch-------->

http://abcnews.go.com/Video/playerIndex?id=4826897



Be Safe

Ken

 

I never knew about this. I think I'm gonna have to go check my tires tomorrow. I never knew what all of those small letters and numbers meant. Great post.

 

thanks for the info. i will make sure my next set of tires are really new. still not sure on the age thing. sounds kinda like global warming did 10 years ago. alot of speculation but no real proof. a few hundred crashes with old tires versuses millions of old tires on the road doing fine. i never worked a crash in 12 years that was caused by faulty tires. mostly faulty drivers and too much

 

I was at Discount Tire yesterday and overheard the sales guy telling a customer that they will not provide any service to a tire that is older than 10 years and they always advise customers with tires that are older than 6-7 years to replace them.

 

Nothing new about that info... Rubber breaks down in air and with sunlight.

 

Not new news. For people who drive the car as a DD they will probably wear out the tread before the tires get old. For those of us who drive our C3 queens a few hundred miles a year it's important check the date code before purchase. Otherwise you can get tires that are up to a few years old before you put them on the car.

I always ask the tire store for tires that are mfg. within 90 days for that reason. For my DD's, I don't really care.

 

Not true...RUbber trees can live for over 100 years!!!

 

For me, six years and they are re-cycled. Both on my DD and my Corvette.

 

Where I work, we work with rubber on printing press rollers. I know the rubber gets harder as it sits on the shelf. After a couple of years, we take all the old, slow moving stock off the shelf and reinspect it. Usually it only gains a couple of hardness points, but sometimes they grow too far out of our tolernace range. It has to do with how much oil was used in the making of that compund. The more oil used, the more it will seep out and cause the rubber to get harder. From what they were talking about in the ads, it seems to be more of a delamination of the tread from the carcus that is the problem. They pointed to the treads on the highways as being evidence, but most of that tread is from semi-truck tires that have been retreaded and has seperated from the carcus. You are more likely to have a problem from a punctured tire. They also stated the tires on that guys van were 4 years old when he bought them. Then then went on to say they were 9 years old at the time of the accident. That is 5 years of driving on a vehicle that is most likely their daily driver. How many miles were on those tires, and how many curbs have they hit or other debris?

So yes old tires can be dangerous, but not if they have been kept out of direct sunlight. I have also heard that there is an ozone type gas given off by electric motors that can effect tire life. That is why they reccomend storing tires in a dark place or with a dark plastic bag over them, and keep them away from electric motors. I think the growing industry reccomendation is to have them replaced every 6 years. Just like any other part on the car, some will be able to go longer than they say they can, and some won't even make it that far. I say if they don't have cracks, and no chordes showing, they should be good to drive on.

 

You need to look at the date on the tires, not go by the date you put them on. They could have been sitting on a shelf for 5 years before you put them on

 

...and typical petrochemical or silicone oil based tire "protectants" only speed up the process.

http://www.303products.com/shop303/i...s-volume-1.cfm

 

Since last summer, I now have personal knowledge of this problem!

My Story
I purchased my 72 about 3 years ago. I knew it was an older frame on restoration, but the seller only had it a short time, and didn't know when the restoration was done.

After I bought the car, I had the car fully inspected, and everything looked great, the tires had plenty of tread, and there was no visible defects such as cracking at all.

Last summer, driving down the highway, doing about 70, and all of a sudden - all heck breaks loose! Luckily the only other person on the road is a little ways behind me - I'm all over the road, both lanes and the shoulders! I'm thinking it's a blowout - but I've had a blowout before, and it wasn't nearly this bad.

The tread had separated on the rear left tire. And when the tread separates, it doesn't do it quickly - it hangs on for a while, and flaps around, acting like a brake!

It's like one wheel has locked up - it's INCREDIBLY hard to control, AND THEN the tread completely comes off, and now I'm on the steel belts with no traction! One extreme to the other!

After I finally get the car under control, I'm down to about 30 mph, and I look in the rear view, and it looks like the guy behind me has dropped a load!

I got it pulled over, and still thought it was a blowout, until I got out and looked at it - the tire still wasn't even flat. I went back and found the tread, and my trim, and center cap.

Now my luck changed, I was less than a mile from a tire shop! They handled it as a defect, and contacted Michelin and started an investigation. For that, they where required to check the tread on all of the tires, and the pressure, and any visible problems - everything was fine, except for the fact that the date code on the tires indicated they were from 97 - 12 years old! And that I'm SOL!

So, I now think that my car was restored in 97, and that's when the tires were put on, and since the rears still had 7/32's in. tread, I'm guessing it doesn't have many miles since the restoration!

I've done a bit of research in this, and have found out that contrary to what others have thought - the problem has nothing to do with the age of the rubber. The issue is with how the tread is adhered to the tire. A long time (I can't remember when), the process that is used to adhere the tread on radial tires was changed, and it's this process that brakes down with age (thermo-oxidative degradation - it's heat and oxidation that destroys this adhesion process). That is why tire companies changed there warranties to only cover for 6 years, after that amount of time, there is no guarantee that the glue will not have deteriorated.

And the real thing that pi$$es me off, is that the tire companies still use an esoteric code for the manufacture date! They warn you to keep the proper pressure, but they don't have an expiration date. Why not??? COST!!! It would cost the tire companies to much because they would have to change their molds!

What

Here's a link to the NHTSA consumer advisory - http://www.nhtsa.dot.gov/staticfiles...inal080907.pdf

 

European tire manufacturers have adopted the six year rule regardless of mileage, appearance and thread. US Manufacturers have been slow to adopt. This article was published in Corvette Enthusiast re Corvette tire safety

Corvette Tire Safety

 

Not trying to argue with you but it seems to me that some of your own comments are in disagreement with others. You state that the rubber rollers get harder over time. Later you state that tires are okay if kept out of direct sunlight. My question is, were the rubber rollers stored in direct sunlight? Could you post where you found the info that states that tires stored out of direct sunlight are okay. If you have reputable data then I will believe it.

 

HI Guys, if you go to this site amd then go to " maintenance" it will direct you to " understanding tyre markings"

http://www.lets-getaway.com/index.htm

When I bought my 79 Vette the tyres looked brand new and still had the molding lugs, when I checked the date from the markings eg
BEVE 4CI 412 this told me thay were 21 years old. Because there was NO triangle at the end this ment they were made in the 41 st week of 1998.

Andy

 

Mashman, I am not sure I understand your complaint. If the manufacturer stamps the manufacture date why not add 6 years to it and you know what the suggested replacement date would be?

I have Coker redline tires on my Nova that were manufactured the 36th week of 2005 (3605). Not sure when the change was made, but the date code is on the redline (outside) instead of the inside which is good. The vette tires were made in 2007 but I will have to crawl underneath to verify the month.

One of the things I have found that contributes to some of these failures is that for the last 10-15 years vehicles that use full size spares do not always provide the same type of rim for the spare as they do for the ones on the ground. Because of that you could go thru 2,3 sets of tires and never put the spare in to the rotation. That tire will look great yet will no doubt be degraded internally.

Years ago my nephew put a spare that was probably 10 years old but looked new on the front of his truck and had the whole belt come off. It happened at about 30 mph so he was able to get it stopped.

Another thing that I have known for years and I am sure others here know is that when buying two new tires that it is better to mount them on the rear instead of of the front. A blowout on the front can be controlled better than one on the rear, especially with power steering. Blow one on the rear and you are going in whatever direction the vehicle chooses to take. Also, less chance of hydroplaning.

I know the above paragraph is subject to discussion but check a few of your local tire stores to see what they recommend.

http://www.michelinman.com/tire-care...ent-questions/
http://www.popularmechanics.com/auto...o/4243992.html