Need 2 rear tires for Z51, some being sold locally here with approximately 1000 miles on them.
Garage stored but 6 years old, are they worth purchasing? Read recently that someone said ZP run flats get hard over time?
What kind of offer would you make on these if any, thanks
Dennis

 

You are going to get all sorts of responses. From "I paid XXX dollars for my Vette so why would I put used tires on it?" to "Tires that old will explode and you will kill yourself and everyone within a 5 mile radius." It wasn't until i joined this forum that I learned tires had an "expiration date". Most of my commute is under 40 mph in a mostly straight line so six year old tires if they looked good wouldn't scare me off if the deal was great.

 

Biggest issue I'd have is that ozone attacks rubber. Even if garage-stored, I'd take a close look at the condition of the rubber.

Other than that, I'd have no issues with used tires with that few miles on 'em

 

"Garage stored" in Florida could mean deteriorated from heat. Or not. Careful inspection in good light, looking for tiny cracks or other deterioration in both the grooves and sidewall, is mandatory.

The week and year of production will be molded into the sidewall of the tires, so you can easily calculate their exact age.
If you just use the car for daily driving at legal speeds, then I'd plan on a life of 7 years.
For high speed work or competition, I'd plan on 5 years.

In the US, there is no official expiration date I've heard, but I use the 5/7 year formula for myself.

 

I have no issues with used tires myself. If they look good and pass visual inspection I'd say go for it. Maybe offer $800 and see if they bite.

 

The new tires - those after 2005 will last 8 to 10 years if stored and kept properly.

The key is to look at the tires as mentioned and look for fading, dry rot and cracking. For normal day to day driving I would take the chance. I would go by the tires manufactured date, not the owners dates.

Here is a tire from 2003 (friends corvette- did damage) with less than 2k miles on it. A pot hole @ 60 mph took it out, you can see how dry the rubber is, no cracking or crazing before the incident.

 

New OEM rears are around $700, other compatible tires much less. 6 year old used rubber wouldn’t be worth much to me on a performance car, but suspect a fair price would be $200 or less for the pair only after mounting and they check out.

 

If no cracks and no punctures then i would say they are good. But make sure you paying significantly less for the used tires. Otherwise, you might as well buy new and know exactly what you are getting.

 

I haven't heard anything about tires made after 2005 having a longer shelf life. Can you provide a link or some details?

 

The 6 yrs in storage part would give me pause.

- Paul

 

I have six year old tires on my 2014 and a visual inspection does not show any signs of cracking, dry rot, etc. The car only has 3900 miles on it. However, I plan to get new tires in the next couple of months just to be on the safe side.

 

The tires before 2005 will last longer, in 2005 they started adding recycled rubber and took out some chemicals - reformulated the tires due to EPA concerns. Tire manufacturers are recommending a 8 to 10 year life for the tires.

The 2005 date is approx. as some manufacturers started the formulation change before that date.

Many automakers, including Ford, Nissan and Mercedes-Benz, tell owners to replace tires six years after their production date, regardless of tread life. Tire manufacturers such as Continental and Michelin say a tire can last up to 10 years provided you get annual tire inspections after the fifth year.

The Rubber Manufacturers Association said there is no way to put a date on when a tire "expires" because such factors as heat, storage, underinflation and conditions of use can dramatically reduce the life of a tire. Here's more on each of these factors:

Heat: NHTSA research has found that tires age more quickly in warmer climates. NHTSA also found that environmental conditions, such as exposure to sunlight and coastal climates, can hasten the aging process. People who live in coastal states and other areas with warm weather should keep this in mind when deciding whether they should retire a tire.

Storage: This applies to spare tires and tires that are sitting in a garage or shop. A tire that has not been mounted and is just sitting in a tire shop or your garage will age more slowly than one that has been put into service on a car. But it ages nonetheless.

Spares: They usually don't see the light of day, but they're still degrading with time. If the tire has been inflated and mounted on a wheel, it is considered to be "in service," even if it's never been used. And if a truck's spare is mounted underneath the vehicle, it's exposed to heat, dirt and weather — all reasons to plan on replacement.

Conditions of use: This refers to how the tire is treated. Is it properly inflated? Underinflation causes more tire wear. Has it hit the curb too many times? Has it ever been repaired for a puncture? Tires on a car that's only driven on the weekends will age differently from those on a car that's driven daily on the highway. All these factors contribute to how quickly or slowly a tire wears out.

Proper maintenance is the best thing a person can do to ensure a long tire life. It is important to maintain proper air pressure in tires, rotate them regularly and get routine inspections.

How to Determine the Age of a Tire

The sidewall of a tire is covered in numbers and letters. They all mean something, but deciphering them can be a challenge. This Edmunds article about reading a tire's sidewall goes into greater detail. But to determine the age of a tire, you simply need to know its U.S. Department of Transportation (DOT) number.

Tires made after 2000 have a four-digit DOT code. The first two numbers represent the week in which the tire was made. The second two represent the year. A tire with a DOT code of 1116 was made in the 11th week of 2016.

Tires made before 2000 have a three-digit code that is trickier to decode. The first two digits still indicate the week, but the third digit tells you the year in the decade that the tire was created. The hard part is knowing what decade that was. Some tires made in the 1990s (but not all) have a triangle after the DOT code, denoting that decade. But for tires without that, a code of "328" could be from the 32nd week of 1988 — or 1978. Really, you can ignore all that: If you see a DOT number ending in three digits, the tire was made in the last century and needs to be replaced as soon as possible.

Clearly, these DOT numbers weren't designed with everyday buyers in mind. They were originally put on tires to make it easier for NHTSA to recall tires and keep track of their manufacturing date.

To make matters worse, you might not always find the full DOT number on the outer side of the tire. Because of the way a tire is made, it is actually safer for the technician operating the mold to imprint information on the inner side of the tire, so some manufacturers will opt to put the number there. It is still possible to check the DOT code, but you might have to jack the car up to see it. Keep the visibility of the DOT number in mind the next time you are at a tire shop and the installer asks if you want the tires to be mounted with the raised lettering facing in.

After checking out a tire's birthdate, give the rubber a visual inspection. Some of the best advice on such an inspection comes from the British Tyre Manufacturers' Association. It recommends that consumers check tires regularly for any sign of aging, such as tread distortion or large or small hairline cracks in the sidewall. Vibrations or a change in the dynamic properties of the tire could also be an indicator of aging problems, the association said. It recommends replacing the tire immediately if such symptoms appear.

Don't Buy Used

Tires are expensive, especially when you factor in the price of mounting and balancing. That's why used tires become more attractive to people who are strapped for cash, and so some small and major shops continue to offer used tires as an alternative. But when you buy a used tire, you have no idea how well it was maintained or the conditions in which it was used. The previous owner might have driven it with low pressure. It could have hit curbs repeatedly. It could have been patched for a nail. You can check its age, but it's better to avoid it entirely.

Make Sure You're Getting a "Fresh" Tire

Just because a tire is unused doesn't mean it's new. In a number of instances, people have purchased "new" tires at retail stores only to find out that they were manufactured years earlier. In addition to having a shorter life on the road, a tire that's supposedly new but is actually old may be past its warranty period.

If you buy tires and soon after discover that they're really a few years old, you have the right to request newer ones. Any reputable store should be willing to make amends. But to save yourself the hassle, check the date before you buy.

Letting Go

Getting rid of an unused spare or a tire with plenty of tread may be the hardest thing for a thrifty owner to do. "Nobody's going to take a tire that looks like it's never been used and throw it out," Kane said. But if it's old, that's exactly what the owner should do.

Although Kane has lobbied NHTSA to enact regulations on tire aging, nothing is currently on the books. A NHTSA spokesman said the organization is "continuing to conduct research into the effects of tire aging" and what people can do to monitor their tires for safety.

Since there's no consensus from government or industry sources, we'll just say that if your tire has plenty of tread left but is nearing the five-year mark, it's time to get it inspected for signs of aging.

 

IMO at least 10 years (if stored properly) is a good rule of thumb. So if the price is low enough, you've got at least 4 more years of driving. There is some small, tiny danger the older the tires get, but it gets blown out of proportion. How many hundreds of thousands of people have driven in 15 yr, 20 yr, or even older tires on classic or on rarely-used cars with no incident? Vs. the very small percentage who had an age-related blowout...

 

BLUE1972-

"The new tires - those after 2005 will last 8 to 10 years if stored and kept properly."

"The tires before 2005 will last longer."

I'm confused, are you saying that tires made before 2005 will last even longer than 8-10 years?
Understanding that there are no hard and fast rules, longer than 8-10 seems contrary to most of the published advice.
Of course, even a tire made in 2005 would now be 14 years old, so it's becoming a moot point.