What is the failure mode for aged tires?

[RadioRoy]

All this latest concern about age of tires has me... concerned. So it turns out that every tire on every car I have is more than 5 years old, some more that 12 years old. Some even older than that, but those are on cars that are not being driven.

What is the failure mode of aged tires? I drive my 60 Lark at 65 or so and my 99 Honda Accord at 75-80. I never (almost never) hit potholes and my tires stay balanced for 60 thousand miles at least on the Honda. That's how easy I am on tires.

I'm starting to get nervous about freeway driving, even in the Honda.

How will the tires fail? When will they fail? There are 45 thousand miles on them now, but I have to check the date code. Will one of them suddenly deflate? Will they burst and splatter me against an SUV or a guard rail? Will they start to go out of balance? Will they just get slow leaks?

Does anyone know?

[tsenecal]

I don't really have an answer regarding automotive tires, but the trailer tires that I have had fail, usually have a cord separation, resulting in a large bulge. I walk around my trailer at each stop, so usually catch them at that stage, and deflate them before they blow out. It seems to be very hard to find good trailer tires. As far as 10 ply truck tires, I have run them for 10 years or longer, without failure, but tire shops don't recommend running longer than 7 years. I drove Hondas for years, and they seem to be very easy on tires. I would think that it might also depend on whether they are parked out of the weather. Two of our cars get to live inside, so the tires look like new, even after a few years.

[T.J lavallee]

The born on date of manufacture is posted on the tire wall. Seven years is the max when it comes to safety. If there's no born on date on the tire you should have chucked it years ago. Better safe than sorry. I change my tires on all my vehicles every five years no matter how good they seen to appear.

[Dads Baby]

Just imagine this. You are driving along with your old tires on your collector car. One of your front tires has a blow out and you cross the center line and hit a family in their compact car and hurt/or kill them. Since you were such a caso on your tires, you were probably a caso when picking your limit of liability so now you will get sued and will probably feel like crap the rest of your life.

OR a little less dramatic: You are driving along with your old tires on your collector car. One of your back tires has a blow out and rips your quarter panel apart causing thousands of dollars of damage to your baby.

A new set of white wall tires from Coker is around $1,000 give or take. A good set of black wall radial from Discount Tire would set you back less than $500. Don't be a caso.

[48skyliner]

Now that I am retired, I don't drive a lot. My six vehicles each get driven between 1,000 and 2,000 miles a year, maybe a bit more on my Geo Metro because it is very fuel efficient and I don't mind driving it in sloppy wet weather. All of my vehicles are garaged when not being driven, so the tires don't get a lot of sunlight. I always check for signs of weather cracking when I have them up on the lift for servicing. A couple have tires more than 15 years old, and I have no concerns about driving then with heavy loads ( my truck) or in any weather or highway speeds. In 64 years of driving, I can recall one time when I had a tire go flat at highway speeds, a front tire, caused an annoying vibration, just pulled over, stopped and changed the wheel. My tires always go flat in my garage, usually from a nail or other sharp object. I think my good service experience with tires is largely because I always run high pressure, more than is optimum for a smooth ride. It seems obvious that high pressure reduces sidewall flexing, which surely is a factor in cracking. I run 40 pounds in my Studebaker tires, 45-50 in my truck, and 35-36 in my others and check them regularly.

This whole nonsense about 5 years, seven years or whatever all started a few years ago when some clever lawyers working for the big tire companies figured out how to intimidate the customers and convince them to throw away perfectly good tires. Of course I realize that some tires sit in the hot sun all day or have other abuse factors that will reduce tire life.

[doug]

One Sunday morning there was a loud explosion. I found the tire on my Champ ripped apart, just sitting there. The tires were nine years old. It appeared to me that the steel belts were all rusty and had seperated causing the tire to come apart. Possibly non-steel belted tires are constructed differently and can are able to not fail for a longer period.

My Lark and Avanti had tire failure on old tires damaging the fenders. More costly than replacing tires.

I check the date code on "new" tires to be sure they are less than a year old, and replace them at 7 years, Period.

[Skip Lackie]

I share both the concern over the safety of 10-year-old tires and the skepticism over how real the danger is. I have a dozen vehicles, and none of them get driven enough to wear the tires out before they reach the age of ten. They all live indoors, so there's little solar radiation damage. A couple of them (64 Daytona with no-longer-made Goodyear 195-75x15s and an Avanti II with 1.25" white wall radials) have tires on them that I can no longer find. Given that circumstance, it's not just a matter of going down to Tire World and pulling out my Visa card.

[Gunslinger]

A lot depends on how the tires are maintained. Is the car garaged or out exposed to sun and weather? Sidewalls can dry rot and crack but cars garaged and tires kept clean and coated with tire dressing can last much longer...at least visually. The interior of the tires can break down regardless of mileage. Tires can look brand new and still age and degrade.

My 2002 Avanti on the TransAm platform doesn't get a lot of use but remains garaged. When the car was about ten years old and still only had about 5k miles the tires started acting as if they were square rather than round. Even with such low mileage the rubber composition has changed and hardened. A new set of tires cured the condition.

Tires and brakes are too critical not to pay attention to. Even the best are barely good enough.

[studegary]

To more directly answer your question - Different constructions of tires have different lives and failure modes. You can not compare old bias ply tires with modern radials. For steel belted radials, usually the failure mode with time (about 10-12 years) is ply separation where a large chunk of tread comes loose or off.
I used to wear out original equipment tires in six to nine months. Now, I drive very little on any one car. I do not remember the last time (decades) that tires that I replaced were worn out (treadwise).

[53k]

A few years ago my son who was moving from Kansas to West Virginia had a serious radial failure. He was driving a one-ton, single-rear-wheel GMC crew-cab pulling a trailer. He put on new (unused tires) for the trip, but date code on them was fairly old. He was driving on I-64 in a work zone where both shoulders were closed off when he heard a bang and the ride changed. He had to drive some distance before he could get off the road. The tread had peeled off the right rear wheel and tore off part of the rear fender and bent the bumper. The tire did not go flat. With installing the spare he was able to complete the trip with no more explosions.

My own personal radial failure was probably 20+ years ago. I had sold my RHD '64 GT (sold new in London) and was delivering it to my buyer near Detroit. We had debated putting new tires on it for the trip, but the buyer wanted to choose his own tires. I was driving on the Ohio Turnpike at about 65 mph when I got a loud bang from the rear. I pulled over and the right rear tire had thrown the entire tread and had gone flat as well. Fortunately I had carried tools with me and I was able to install the spare (I hadn't even checked it for inflation before I started out). While the peeled tread didn't do any body damage, it did break both LP gas fillers behind the right rear wheel and under the right rear quarter panel. I lost about 80 liters of propane. I was running on gasoline so I wasn't dead along the road and I finished the trip on gasoline and a questionable spare. I should have known better than to start out with Michelin tube-type 195x15 radials. They probably dated back in to the '60s.

My one near-miss was on a Cooper radial. I had put a set of Cooper 225x75x15 radials on the car in Kansas (driving the car from California to West Virginia) because it seemed like the old radials were very hard. I didn't like the Torque Thrust wheels on the car so I took the car to a friend and had his crew remount the tires on a set of 6-inch steel rims he had. A few days later I noticed a bubble on the sidewall. I took the car to a local Cooper dealer. He said that whoever mounted the tire was pretty careless because the bead was damaged and the tire wouldn't have lasted much longer. So, rather than drive 200 miles to get my friend to make it good, I just had a new Cooper installed.

[Jeff_H]

I made a post about what happened to the OEM tires on my 2004 F150 when they were about 11yrs old back in 2014:

http://forum.studebakerdriversclub.com/showthread.php?83742-Bad-tire-bad-trip-home

[Buzzard]

Tire failure

OK Roy and guys(and girls),
40+ years in the tire and wheel industry has let me see just about everything related to tires.
Firstly, lets remember that the construction and materials have changed immensely. Bias ply became bias belted, nylon gave way to rayon and other polyester materials and ultimately then radial construction became the norm with steel belted tires as well as kevlar for belt support and strength. Our original tires from 60+ years ago were mostly made with real rubber. These tires were supported from the inside with very robust and forgiving tubes and liners. Now most tires have very little rubber, are of tubeless construction and are mostly made from synthetic materials which are very susceptible to breakdown from ozone, temperature and sunlight. We used to receive letters from Michelin, Goodyear, Yokohama, Toyo, Bridgestone and several other major manufacturers requesting us to not press a tire into service if we knew the tire to be over six(6) years of age. There is a lot of lee way here as the manufacturers are covering their own butts in this age of litigation with absolutely no one wanting to take responsibility for their own lives. Modern tires deteriorate from the inside out so mostly it is near impossible to foresee a tires' impending demise unless it is physically separating and the tread is distorted.
Another factor is where the tires are being used. There is no way Bob in Phoenix will have a tire deliver the same range of service that Rich in Washington state or Gary in the northeast would receive. Heat is a killer. Those living in snow zones also usually have two sets of tires which greatly extend all 8 of the tire's longevity and performance. All 8 will also be rotated twice a year which also helps in longevity and smooth performance. Remember the Ford Explorer/Firestone fiasco back in the 90's. The initial failures were from the high heat areas of the country such as Arizona, Texas and California where not just the ambient temperatures were high, but also speed limits as well which create more flex and thus higher than normal temperatures in the tires themselves. Part of the failure was due to Ford trying to get the ride quality acceptable in an otherwise truck chassis by labeling the door decal ratings to 26 PSI. It matters not what brand of tire subjected to those initial low pressures, normal human neglect(most cars' tires are usually approximately 8-10 psi UNDER the recommended pressures) will inevitably lead to failure with extreme flex and subsequent temperature increase. We in this forum are most probably more anal about our tires' pressure and condition than the average car hating individual who sees a car as a simple device to move one around.
I carry a laser temperature gun and when stopping for fuel on a long trip, I shoot each tire for a temperature reading. It hardly matters what temperature they are at, but rather the differential between the tires. For example, if you have just come off a 70+ mile per hour run for hours on end, all the tires should be running at fairly consistent albeit somewhat higher than normal temperatures and pressures. If one is considerably higher than the others, it is showing that it may have picked up a nail or in the case of this conversation, is starting to separate from age or normal degradation which causes excessive flexing of the tire, and thus higher pressure AND temperature.
Like Gunslinger, my '83 Avanti rarely gets driven but last year while travelling to our local chapter meet, a discernible vibration was being transmitted from the otherwise great looking Michelins which I know is a factor of age degradation rather than obvious tread wear out.
To be safe to both our well beings as well as our wallets I recommend replacing your tires every ten(10) years to err on the side of caution and safety. I hope this long winded explanation assists some of you.
Happy Studebaker driving.
Bill

[t walgamuth]

My sorry tales of too old tires is with trailers. I've had two blow out doing significant expensive damage to my travel trailers. Around town is one thing sustained high speeds is another.

Better safe than sorry.

[jnormanh]

What is the failure mode of aged tires?

To answer the original question:

Ignoring mechanical damage, running over curbs. deep potholes and the like -

1. Tires fail because of internal separation of the reinforcing plies. This was a larger problem in the past than it is now with modern rubber compounds and radial construction.

2. Tires also fail because the "rubber". which hasn't been real tree rubber for nearly a century, ages and oxidizes and loses strength because of heat and especially because of UV, ie. sunlight.

Modern tires are far more resistant to sunlight degradation. Even parked outdoors, they're usually good for ten years or so. Continuously garaged away from sunlight, maybe twenty years.

At twenty five years, I'd replace them "just in case".

Check your tire pressures often enough, park the car away from sunlight, and they'll last long enough to scare you into buying new ones.

This isn't 1960 when tires "blew-out" with some regularity. When's the last time you saw someone pulled off the Interstate with a blow-out?

I'd also include a story about tire quality. Many moons ago our daughter had a Toyota which needed new tires. I took it to the Western Auto which sold many brands and bought four new tires, two high-dollar Michelins (about $45 ea) and two store brand ($17 ea). I rotated them every 5000 miles. After about 30K miles, the Michelins were worn out, and the cheapos were good for another 30K.

Ever since I've bought the cheapest tires I can find. Never had a low-out or other sudden failure.

[rockne10]

My experience with bias tires, 25 years. With radials, 10 or less. But there are too many variables to even begin to think there might be any hard and fast rules.
Best advice, which most others have given: check them often, check pressures and maintain recommendations, look for any dry cracks close to the rims and between the grooves in the tread. Listen for any tone changes while driving or feel vehicle wallowing when negotiating the slightest curve. "Thump" them with a tire iron (like the professionals do).
And, when you think they might still have some life left but you're not sure...turn them in to a backyard swing.

But, should you experience a sudden "blowout", even on a steer tire at highway speeds, DO NOT PANIC, DO NOT SLAM ON THE BRAKES. Just release the accelerator and calmly steer in the direction you want to go. If there is little traffic you can let the car slow itself down. BTDT.