Replaced the tires on our 2008 Expedition July 2013 at Costco (Dueler H/L Alenza). They have 35,700 miles on them. Tread depth is good on all 4 but am wondering whether because of the passage of time,and the fact that the vehicle is not garaged,they should be replaced regardless.

Look for cracks on the sidewall due to age.
If I was going on a long trip somewhere they'd probably get replaced.

Unless they are damaged, no I wouldn't replace them, take it in have them rotate, check pressure and alignment, if they pass muster then carry on...

How Long do Tires Last

How Long Does a Tire Last?

Carmakers, tiremakers and rubber manufacturers differ in their opinions about the lifespan of a tire. The National Highway Traffic Safety Administration (NHTSA) has no specific guidelines on tire aging and defers to the recommendations of carmakers and tire manufacturers.

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.

Funny you should ask. My Silverado has been sitting for a touch over a month because it won’t stop raining and I need to swap out the transfer case motor as it is stuck in 4wd.
Finally had a little break in the weather and the neighborhood came over to play out back where she resides. I noticed the ol’ Silverado was leaning a bit.




These tires are 8 or 9 years old (garage kept for 6 of those) and maybe 30k miles.

I would replace them. I was planning to replace these anytime now.

With tires, I err on the side of caution. Over that period of time, I'd replace them if they are on an important vehicle or one that you rely on.

If your tread depth is still passable (at least 5/32") and there is no sign of sidewall cracking, or cracking between the treads, it doesn't sound like you really need tires right now. 2/32", or when you see wear bars …



… is considered worn out. I don't like to let mine go that far; I like to replace them at 4/32".

quote:

Originally posted by MikeGLI:
With tires, I err on the side of caution. Over that period of time, I'd replace them if they are on an important vehicle or one that you rely on.

+1 When it comes to tires your life is riding on them, a failure when you are going 70 mph on the highway could be fatal.

Egregore has it. Check tread depth, inspect sidewalls and treads for cracks (preferably on a lift or with the wheels removed). If all is good keep driving. I change mine early so I don’t wait for the wear bars. Heavy rain or flooding things can get squirrely.

I'd replace them. Helped a friend change out two during a day trip that were less aged than yours. Second was in the dark, on the interstate on the South side of Chicago. Think we may have set a time record getting that one done.
Years of MC riding really demonstrated to me that we don't notice the degradation in handling and performance over time as it happens slowly. Every time I got a new set of tires on a MC it was like riding a new bike.

"Unless they are damaged, no I wouldn't replace them, take it in have them rotate, check pressure and alignment, if they pass muster then carry on..."

That's what I would do. Check the air pressure frequently, drive sensibly, inspect for cracks / damage, and you will be fine.

The last set of tires I had on my car (Hankook Optimo, a "middle of the road" price-wise tire) totally hydroplaned trying to stop on a steep downhill grade in the rain (and I was already going slow), and they still had 4/32" tread. They got the boot not long after that.

If all you do is putt putt around you shouldn’t have any trouble.
I borrowed a pickup that had tires with some age on them. One of those tires failed and caused a roll over accident. Pushing your luck is just not worth it.