Technical Tire deterioration / When should you buy new ?

Sun , weather elements etc break down tires over time. For most of us our old cars are inside most of the time,not exposed to the ( sun) being the worst & the rubber does not break down as fast as if they were outside all the time. Don,t quote me on this but I believe here in Mn the DOT says 7 yrs is max for a tires life, no matter what ,over that & they are considered dangerous even if the tire still has a lot of tread on it. So do most of you just judge your tires simply by the tread left ? I guess I do. Today I was on the ground next to my old car & saw one of the tires, the sideway had cracks in it; other than that it looked perfect. It pays I guess to pay attention to ones tires ! Gene in Mn

 

I was driving around my "new" old car yesterday, and it had a bit of a "wup-wup-wup" feel/sound to it. Today, I jacked it up and looked at the tires...the oldest one has a nice bulge in the tread, where it's coming off. And the tread is still nice and deep.

I'll drive around locally on 10 year old radials, but won't go on a trip with tires that old. Even if they're kept indoors most of the time.

 

A friend of mine had 9 year old radials on this F 100, the rubber on a rear tire came off while he was going 50, damn near killed him. It can be risky !

 

3 years ago I replaced the tires on my beater just before the all Deuce run, the tires had plenty of tread & were not cracked or showing any signs of dry rot but I was thinking about driving 400 plus miles in one day and the temperatures were going to be in the 90's.

I had been driving around on tires that were over 20 years old, what's the old adage about fools and drunk's? I sure pushed my luck.

My tire must have been made prior to the Firestone tire exploding debacle. HRP

 

Geez, all that at only 50 mph.

 

20yrs ago I had WW's on my OT 66 Ford and on a trip when the tread separated on a rear tyre at 60mph exposing the belts. Some days later the other rear tyre did exactly the same thing. These tyres were new and hadn't been driven on in 2yrs when I was building the car. I made sure that they were stored correctly in that time. I ended up replacing all four (4) tyres new WW tyres, running a box cutter through the remaining two (2).
A few years ago I was driving was 35 tub and turning into a low speed corner when the LHF tyre suddenly failed. When I checked it I discovered that the tyre case had split with multiple cracks at the base of the tread. These were 10yr old tyres by this stage and not high mileage or absued. I ended up swapping four (4) new tyres and box cuttered the other front tyre, giving the rears to a friend as set up ONLY tyres, on the proviso that they weren't to be driven on in case of failure. I make a habit now of regularly checking my tyres.

 

I've lived by the words my father told me about putting a vehicle together. Tires and brakes last.

Kinda makes sense and has worked for me, I mean what happens with 5 year old brakes, 8 year old tires, when you get it on the road? They might be okay, but you still going to replace them soon.

Why do it twice?

 

I would check the date code, and probably wouldn't run tires with cracked sidewalls.

It'd be tough to throw out old tires that aren't cracked.

 

He ran off the road, through a ditch, and over it went. He is an excellent driver, Drag Raced for many years, won some National Wallys.

 

In most driving situations, it wouldn't take much. A head-on (or offset) collision at 25 mph each is similar to a 50 mph collision.

 

When I got done building my coupe, a friend gave me a set of 4 Michlen radials that were over 15 years old, and still had great thread. Since I didn't have any other tires, and no money at the time, I put them on the car. The car was pretty much just driven locally and it rode and drove great, but I did watch them pretty closely. About 2 years later we were planning on taking the car on a longer trip, so I bought a new set of tires to replace the Michlens, that we had put nearly 8,000 miles on. When I pulled the Michlens off, they still looked great. The guy at the tire store didn't seem to care how old the tires were, but he was pretty amazed I was changing them for new tires. I don't know what he did with them after I paid him the recycling fee for them.
The tires I replaced the Michlens with just got replaced last week, 7 year old radials with 42,000 miles on a 40K tire, still had 5/32 thread. I think one of the front tires had a broken belt because I recently developed a small vibration through the steering wheel. I replaced those tires because of the vibration, and because the rear tires had poor traction on wet roads, and because of the age of the tires.

These days, I think any tires older then 8-9 years is probably pushing your luck, even if all indications are the tries are OK. I also wouldn't hesitate to replace a 5-7 year old tire if it showed any signs of a problem, like a vibration, a pull, any strange tire wear, any cracks in the thread or sidewalls, or a tire consistently loosing air for no apparent reason. I drive my stuff to much to take a chance on a tire issue. Gene

 

Liability may be reason for concern. I am reasonably sure that if your old tires were determined to be the cause of an accident, you may find yourself in a shitload of trouble. God help you if someone gets hurt, or worse.

 

All this business about 'tire expiration' came out of the Ford Explorer/Firestone tire fiasco. The NHTSA, Ford, and Goodyear all ran various tests. At the end, the NHTSA came out with a recommendation of six years max life. What they didn't tell you was they ran the test in Phoenix Arizona, the most brutal urban environment for tires in the US. They initially released a 'draft' copy for public comment that I downloaded and read. The appendixes detailed the various test procedures among other things. There were lots of nuggets to be found.... The currently available document has all this missing....

1. Yes, tires will age from heat/UV exposure. But what they failed to tell you is the rate is exponential by temperature, not linear. Phoenix has an average daily temperature of 90 degrees, if you live somewhere cooler, your tires will age considerably slower. If you live in the sunbelt, you need to pay more attention than someone who doesn't.

2. The NHTSA also researched three (or maybe five, I can't remember) years of accident reports from all 50 states and was unable to find even one documentable case of an accident solely caused by an 'aged' tire. Leading causes of tire failure? Road hazards, and followed closely by underinflation. Which brings us to...

3. While it was never directly admitted by either of them, the Ford/Firestone problem was that Ford recommended a 'soft' inflation pressure to improve ride, 22 PSI IIRC. This low pressure coupled with high heat in the sunbelt led to tire failures. While neither biasply or radials like low inflation pressures which will generate heat in the tire, a biasply tends to distribute the heat more evenly, while on a radial it's more concentrated in the sidewall and will lead to quicker breakdown of the sidewall. So if you're running your radials 'soft' to help with ride quality, it's not a good idea. That could have easily been the cause of the wreck in post 3...

The idea that tires become 'dangerous' on a magical date is ludicrous. Tires fail, even new ones. Ask any tire manufacturer when their tires become 'dangerous' and not one of them will give you a date. At most they'll 'recommend' that after a certain amount of time (between six and ten years for the ones that even offer a time period) you should have them 'inspected' by a 'tire technician' to see if they're still 'suitable for use'. If you run into a tire 'tech' who does more than just look at the date code, let me know; I haven't met one. And while the manufacturers were wishy-washy about this, the retailers thought it was great. What could be easier; 'your tires are too old, we won't service them. We can only sell you new tires' requires little salesmanship.

At the end of the day, it's still your responsibility to maintain and check your tires.

 

Agree with all that @Crazy Steve said above.

Will just add that there is not an exactly definable age when tires become more susceptible to failure. It is an "ageing process" that has a multitude of associated variables. The replacement age defined by law is just a line in the sand that had to be drawn somewhere.

More to the point, regarding liability, in these times of there being a need to lay blame for all and every incident, you can be sure that everyone will be trying to pass the buck to someone else. Often, the determination of guilt in our legal system hinges on who runs out of money first. Best not to place yourself in the situation. Change your tires by the date stamp. It's a good insentive to spend more time in your ride making sure you accumulate some tire wear and get your monies worth.

 

The whole thing was about liability... the manufacturers mostly. Remember, the NHTSA did not codify this into either law or regulation, they merely issued a 'recommendation'. This, along with weaselly-worded additions to their warranty page, let the manufacturers off the hook for any tire failures past this 'recommendation' period, no matter what the fault was.

As to personal liability, re-read point two above...

 

I changed the tires on my car out two years ago- I replaced Michelin’s that had been on the road 13 years and had been mounted for two years prior to that. They had about 40k miles on them and looked pretty good but we’re developing some minor cracks between the treads. Not worth the risk to me of having a blowout and destroying a fender or paint or loss of control and who knows what. There is value in peace of mind

 

Seven year old tire ....bad Seventy -year old suspension parts.....vintage....???!!! All stuff sitting under yer ass.......Still kind of a double standard, I'm thinking

 

I have had too many friends experience damage to their sheet metal from "good" older tires coming apart for me to risk it. Heard too many stories of destroyed hot rods due to blowouts to risk it. Michelin says 10 years on theirs and that is the brand I prefer so that is the limit for me.

 

Steve is spot on about everything he said. Another thing that came out of the Ford/Firestone debacle was the federally mandated Tire Pressure Monitoring System (TPMS) that is required. TPMS is obviously off topic for our cars, but an interesting bit of trivia.


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It looks to me like the problem with tires and age, is that the rubber bond to the steel belt "goes bad" over time. Heat makes it happen faster, but it seems to happen all by itself, regardless of where you live.

I've had a steel belted radial explode while sitting in a stack, in my garage....old radials are like a time bomb.

 

I had tires that were twenty years old, only had 10,000 miles on them. Drove good, rode good and looked like new. I always keep the truck inside climate controlled garage and kept the air pressure right. I replaced them due to the 7 year recommendation. New tires ride better and I feel better about having them. I shopped around for rebates and discounts and ended up with four new tires for about $250. Couldn't be happier, sold the old tires on Craigslist, showed the guy the date code, he didn't care, paid me and off he went.
Tire brand has as much to do with tire safety as age does, Michelins will out last most any tire if you can afford them.

 

This is a widespread misconception. When two identical cars collide in a head-on collision, each will come to a stop exactly as if each collided with a perfectly rigid wall.

 

Probly time to quit buying my tires off Craigslist.

 

I haven't had time to run my car this year because I'm swamped with work , but the other day I thought about taking the car out and realized that my tires are now 14 years old . I really looked the tires over and they still look good as they have no cracks or bulging but I don't know if it's worth the risk .

 

In a head-on collision the two speeds are added.

My main point is that even driving at a slow speed, where one might think, "I'm only putting around on these old tires," a tire problem could easily become a bad collision.

 

The owner of a tire shop told me that he has had spare tires in the back of trucks blow up while sitting in the drive. Us older guys ran old tires and nothing happened. Newer tires are bombs waiting to go off after 5 to 7 years. I have no idea what's different but it is. Most of the pics I saw were BFG radial ta's. That was probably the most popular tire so you can't assume they were more prone to failure.

 

With the twistys we have here, tires usually last me two to three years with 10-15k miles.. I have my suspension updated for excellent handling. The alignment has lots of Positive Caster and Negative Camber..

 

I'm in the tire business, what Crazy Steve said was good info, i personally would recommend after 6 or 7 years. HEAT is the worst thing for a tire, running low air pressure makes your tires heat up faster causingbreak down sooner. I don't see tires coming apart on today's tires unless a road hazard has happened. But if you thousands of dollars in your car, then don't be cheap but not replacing them

 

I think you're right, pretty sure that Myth-Busters did a show in it with shock gauges.

 

Search for "Myth Busters head on collision" episode.