Technical 64 Impala riding on 27 year old tires.... Too old?

Some of you guys need to be educated about tire construction.

Nearly every tire ever built that is designed to hold air has steel in them. The tire beads are all steel reinforced except maybe light duty bicycle or wheel barrel tires.

A pair of nylon (cheap tire) or a polyester (expensive tire) corded fabric runs between the two steel tire beads. On a bias tire, those two fabric cords run across the tire at about a 45 degree angle from one bead to the other with the cords laying in opposite directions forming an X pattern.

On a radial tire, those two fabric cords run straight across the from one bead to the other forming a double layer of straight lined fabric across form one bead to the other. Both tire constructions are covered with a rubber mix. That is the only difference between a bias tire and a radial tire construction. When you read about a 2 ply, or a 4 ply, or an 8 ply tire, it simply tells you how many layers of the corded fabric are used in the tire construction. Those numbers are always even numbers. The more layers of fabric, the more stiffness the tire sidewall has, and the more load that tire can carry.

Tire makers soon figured out that if they added a layer of corded fabric material around the center of the tire, but only under the tread, it would stiffen the tread under load and would resist tire puncture. The extra benefit is the tire tread would wear longer. Those are called the tire belts. The tire belts were made from a lot of different materials along the way. The belts always have the cord material running across the belt at a 45 degree angle and are about the same width as the tire tread. The tire belts are held in place by the rubber bonding.

The steel in the automotive world that causes the problems are the "steel belts". The steel belts are a pair of a wire mesh strand construction that lays under the tire tread. A common problem with any tire belt is the rubber bond is the only thing holding the belt in place. As the rubber ages, or gets hot, that bond can (and does) break down and allows the belts to shift under the tire tread. That belt shifting is the cause of most tire failures that happen before the tread wears out. The steel belts have a higher failure rate because the steel holds the heat longer then other material usually does causing faster rubber breakdown.

Not all radial tires have steel belts in them. The steel are "belts" added to the tire construction under the tire thread.

Bias ply tires can also have steel belts in them. A couple years prior to the radial tires becoming popular, the steel belts were first added to the higher quality bias ply tires that were "high mileage tires." The steel belts were added under the tread so it remained more flat to the road surface as the tires rolled along.

Because the radial tire has the cords running across the tire at 90 degrees to the road surface, the tire tread tends to remain flat on the road and the sidewall flex.
Bias ply tires with the x cord shape tend to not flex as much in the sidewalls, so the flex takes place on the tread surface, causing them to wear faster. Adding the belts to the bias tire really improved the tread life.

So the OP has determined to replace his tires, which is a good plan.

Any tire that makes it past 10 years is a time bomb waiting to go off, you have no idea how much the rubber has deteriorated.

Any belted tires probably reduce that time frame to 6 to 7 years before that time bomb goes off, because the bond on the belts can allow them to shift faster.

Any steel belted tire , probably much past 5 years is pushing that time bomb.

 

Anyone with a 27 year old condom in their wallet just might be overly optimistic.

 

I had 14 year old tires on my 49 , the steel belt separated, damn near shook the car apart. I didn't know they were that old, learned a lesson there.

 

When I bought my 56 Ford I bought a set of Diamond Back whitewalls radials. They were on the car 5 years and 5000 miles. They are in my lock up on the original rims. They were replaced with a set of Hankook radials when I went to Torque Thrust wheels. They have been on 6 years and I’ve put 6000 miles on them. Next January they will be replaced. I’m sure they would have been 40K tires if daily driven.

 

Your car, your life, and possibly your family....... Now- do you feel safe?, or just asking what the rest of everybody would do?......... Kinda a no brainer!

 

You owe that tire shop big time................... assuming you get on well with your wife.

Thank you @gene-koning . That is one of the best, most informative and well delivered posts I have seen with regards to tire construction and life-span. There is always lots of debate about this subject. I am sure it is financially driven, when it really should be the safety aspect that is more important.
I really enjoyed your unbiased (pun intended) input of the real facts.

 

There are rubber curing chemicals used to cross link the rubber embedded in the tire. Tires are pressed under heat and the chemicals stitch together the molecules of rubber. Problem is they keep working, more slowly at room temperatures. So after ten years the rubber is too cross linked and cannot flex the same way, so it builds up extra heat. That's why a 25 year old spare, never seen the sun, have been mounted can blow out suddenly on the highway. Google "what does tan delta tell you"... (I work in a synthetic rubber plant)

 

Interesting stuff guys, thanks for all the feedback....I knew the thread title would draw some good feedback and hard data. Appreciate the knowledge sharing.

 

Corvette style Rallye wheels look good on a 64, as do Daisies (American Racing 200S), Cragar SS, even Keystone Klassics can look good and harken back to days gone by.

 

Welp... I guess I better get those 30 year old bias ply bomb's off of my bucket of bolt's. @KrucksGarage, thank you for bringing this up and making me check the date's on my junk before something bad happend. Didn't realize they'd been around that long!

 

Thanks for the detailed explanation. Although bias ply tires that are 20 years old don't scare me, as much as steel belted radials that are 10 years old. There's something about that rubber/steel bond on the belts that just doesn't hold up nearly as well as the rubber to cord bond on bias ply tires.

 

Or overly picky!!

 

I have a 27 year old broken condom who now has a little broken condom of her own.

 

Any tire with steel in the tread and sidewall will fail AT SUSTAINED HIGHWAY SPEED before a fabric corded tire. The killer is heat! Steel generates more heat while flexing, and also holds that heat longer than fabric threads. Underinflation causes more heat to be generated as the tire flexes. In reality, there is no "one answer covers all questions" when it comes to tires!

 

yeah, but the steel belted radials even blow up just sitting there....it's happened to me....

 

The steel belted bias ply didn't do any better, they just didn't produce as many steel belted bias ply tires for as long or in such numbers as they produced the steel belted radial tires. You don't hear much about any steel belted tires these days, I don't believe anyone is making them anymore.

Again, the only steel in the sidewall of a tire is at the beads, no place else. Every automotive tire I've ever heard of, past or present, has steel in the tire beads. I've never heard of steel else where in the sidewalls.

The steel belted tires held up well at legal sustained highway speeds for 5-6 years for the most part. Excessive speed, or low air pressure, or aged out rubber, caused a problem with more steel belted tires then other belted tires for sure. Probably part of the reason no one (that I know of) sells steel belted tires of any kind anymore.

 

Well, let me ask, is there steel in the glass belted tires as well? Been since I was a teenager since I recall them.

 

Depends on how you have been storing them.
https://www.goodyearrvtires.com/tire-storage.aspx
How to Store Your Tires
The best place to store tires is a clean, cool, dry, sunless area away from strong air currents. Even though the rubber used to make tires is formulated to resist the effects of sunlight, ozone, and water, the life of a tire can be extended if exposure to these elements is minimized during storage.

• Stack tires flat so that the bottom tire will maintain its shape
• Wrap each tire with an opaque polyethylene covering to minimize the effects of oxygen and ozone. Most Goodyear retailers have storage bags made specifically for this purpose
• If tires are being stored outdoors, they should be raised off the storage surface
• If tires are stored while mounted on rims, they should be inflated to 10 psi
• If they are put in storage during warm weather, the initial inflation pressure should be about 15 psi to offset the pressure drop during cold weather months

 

I store tires in a homemade rack where the tire stands on two beveled edges to match the curve of the tire and spread the tire weight. ( think of a length of 3"x 3" cut in half lengthwise at 45 degrees ) Better than a square rack that can eventually leave a small dent in the tire at the resting point. Pitch dark and cool. Stacking tires that are not inflated for a longer time is not good for the bottom tires . A good old vintage style tire weighs at least 10 or 15 kilograms so the lower ones become cracked pancakes in time.

 

So we instinctively know this shit as car folk. This just gives a bigger twist of the head as to why so many buy new tires so soon in a restoration or build project. You know it'll be a few years yet there's 4 new tires on it. I see it a lot in restoration, someone bought a car doing a body off restoration but there's always new tires when it gets sold unfinished, the seller proudly proclaims "...1st thing I bought for it...". Once or twice I'd never notice but it's like virus and really bad with racer types. I've avoided project buys the last 2 years but this trend has spanned decades.

 

^^^^^ Nursery Syndrome, how many mothers assemble a nursery only to miscarriage?

 

The beads have steel wires. Since the cords wrap around these, they are not dependent on the steel to rubber bond to stay in place.

 

While I, "some what agree" on the financially driven statement, you guys sound like old women.
That's right, your a bunch of old grannies and if I had a Homer Simpson voice I'd use is now.

"Oh, I have to replace my tire cause there old."

How to Know When You Need to Change Your Tires to Avoid Blowout (utires.com)

If one half of American's got out to fill there tire with "free air", no fear of being charged a buck or two, maybe you wouldn't have the under inflation problem. If they still metered your "free air" to the pressure you set, ding, ding, they would have a reason to check it's accuracy.

If most could afford a truck, would they over load the family station wagon?

I want to thank you for being so concerned with my safety. Maybe we should pass another law to make it mandatory. Add another layer of government to monitor and enforce it.

Most Common Cause Of Tire Blowouts | Endurance Warranty

6. Old/Defective Tires
As with all car parts, the older they are, the more likely they’ll experience part failure—and tires are no exception. The more road trips they take you on, the thinner the tread becomes until a blowout is bound to happen. Sometimes, however, age isn’t the issue. A brand-new tire with a manufacturer default can be just as dangerous.

Old bald tires are traditional, and were usually found on the cars of the poor working class of joe stiff, not the rich retired hot rodding hobby types with six figure cars.
A Christmas Story The Flat Tire - YouTube

 

It’s not just your safety, you share the road with other people as well.

 

I realize this was on a travel trailer but I had a load range E spare explode while mounted on the rear of the trailer. Zero miles, never had been on the ground. Broke the rear window and knocked of a clearance light when it went. The rear of the trailer faced west so I guess the combination of the high PSI of the spare and the SoCal sun heated things up but it couldn't be as much as the heat generated running down the freeway at 55 MPH. After that I removed the spare and kept it in the shop. And yes, the tire was made in China but I've never been able to find ST rated trailer tires not made in China.

 

do you carry full coverage? Insurance might not pay out if an accident happen and the tire/s were the blame.

happened years ago here. A guy came to the board many moons ago and asked us about insurance after he totaled his 1940? ford when a back tire blew out and he rolled it. His insurance wouldn't pay because he said his tire blew in the report causing the accident and his tires were something like only 6 years old but hardly any miles on them. So insurance denied his claim but the good news is they found out his wife had early stage of cancer and she received treatment in time. without the accident who knows how long before she realized she had cancer.

 

This is real. It happened to me. Old tires looked good. I knew better, and planned to replace them, but I was just driving a few miles from my house. The tread blew off the right front tire on my '49 Merc. It flapped around the wheelwell, dented the fender, knocked the headlight OUT OF THE FENDER. If you don't care if your car gets messed up, maybe think about the other people on the road (Me, my family, you, your family) that might be driving in the other lane, or in your passenger seat, when your tire blows. Is any of that worth saving a few dollars on tires? On a completely different note, why the hell are you not driving your car enough to wear the tires out in 27 years?

 

Wish I was riding on a 27 year old.

 

Like squirrel said.
Plus, the "Glass belted tires" could have been radial ply tires or bias ply tires with 2 fiberglass belts under the tire tread. The fiberglass was just another form of several materials tire manufacturers used to stiffen the tire tread surface for the on the road contact point.

 

I wish a 27 year old was riding on me!! (I'm old and lazy)