[MatthewKlein]

Originally Posted by srmmmm

Ozone and UV exposure still occurs in storage that starts to breakdown the sidewall and tread compounds.

I'm familiar with UV breaking tires down but incredulous that would take place in a warehouse. Years ago I saw a 1969 stock car at a car show with what were claimed to be period slicks. Was told the tires had not been in sunlight and were decent enough to drive on yet. He did say that he didn't trust them over 60mph.

I had a set of tires for my own car in the shed for over 10 years before using them last summer with no issues. Now that I'm thinking about it the front tires on that car have been on it since the early 2000's. They are fine.


Regarding the rest of the issues people are discussing we must be lucky.

I have a small auto shop. We sell tires. Unless a customer has a brand preference we sort the tires least to most expensive. Then go down the list to find a tire with a 600 or more treadwear rating. I can't remember having to add excessive weight a tire ever unless the rim is bent.

[HWYSTR455]

As a reminder, tires are really only good/safe for 5-7 years, and that's the upper limit. Homework it before you blast me.


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[72projectbird]

Originally Posted by HWYSTR455

As a reminder, tires are really only good/safe for 5-7 years, and that's the upper limit. Homework it before you blast me.


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Yeah, I'm not spending $1400 every 5 years.

[nas t eh]

Originally Posted by HWYSTR455

As a reminder, tires are really only good/safe for 5-7 years, and that's the upper limit. Homework it before you blast me.


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Some experts say 6-10years depending on storage conditions. All the experts are being a little conservative and while some of the tire’s aging goes unseen, if you are willing to check the tires visually for fitness you likely can push that time frame some.

[HWYSTR455]

I've been on 2 Hot Rod Power Tours, and you would be surprised at how many cars I passed between stops were on the side of the road with tires that failed.

Most if not all of those people were running old tires, which looked perfectly fine visually.

When you have a tire come apart on you on the highway, and it whips your quarter panel to death, THEN you will swear to yourself you will always replace tires at proper intervals.

Before you even mount tires, check the date on the tire. I've seen some tires come from a warehouse that are already 3-5 years old.

14, 15, and 16 inch tires are no longer very common, and have the greatest chance of sitting in a warehouse the longest. 17s are right up there too.

If you push the envelope on tire age, and accept the risks, I wish you luck. It costs a lot more than a set of tires to repair a quarter panel, or any panel for that matter.

In my experience(s), being cheap never ends well.

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[Formulajones]

Originally Posted by HWYSTR455

I've been on 2 Hot Rod Power Tours, and you would be surprised at how many cars I passed between stops were on the side of the road with tires that failed.

Most if not all of those people were running old tires, which looked perfectly fine visually.

When you have a tire come apart on you on the highway, and it whips your quarter panel to death, THEN you will swear to yourself you will always replace tires at proper intervals.

Before you even mount tires, check the date on the tire. I've seen some tires come from a warehouse that are already 3-5 years old.

14, 15, and 16 inch tires are no longer very common, and have the greatest chance of sitting in a warehouse the longest. 17s are right up there too.

If you push the envelope on tire age, and accept the risks, I wish you luck. It costs a lot more than a set of tires to repair a quarter panel, or any panel for that matter.

In my experience(s), being cheap never ends well.

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Yep I've had tire failure at 70 mph on my truck. $3500 damage. I've had them blow more than once on my trailers too. It's not fun.

It's a fairly common theme in Arizona during the summer. Seems to always happen most during the hot months.

Never once had that issue living in Ohio. I think the intense sunshine in AZ and the really hot blacktop is a factor. I've gotten to the point when tires get over 5 years old I start getting leery of them. I might run them longer if they still look good but I tend to keep the trips shorter lol.

[mgarblik]

Originally Posted by srmmmm

Ozone and UV exposure still occurs in storage that starts to breakdown the sidewall and tread compounds.

Non-popular sizes from smaller warehouses are often where the old/new tire issues come from. Especially trailer tires. Be sure to check those date codes! I bought 4 trailer tires years ago that were 9 years old when I received them. Sent them right back. After 10 years, your on borrowed time.

[Shiny]

I'm always curious about what makes stuff break. I found what I think is a decent summary of the tire aging topic with a lot of references to NHTSA and some interesting insurance industry data:

https://www.liveabout.com/the-scienc...-aging-3234377

My takeaways:

- Oxygen in the air permeates the tire and chemically degrades the rubber and/or interface adhesion. UV exposure is NOT the primary factor.

- Pressurized tires have more oxygen, so degrade significantly faster than those in storage.

- Heat accelerates the processes - both diffusion of the oxygen and the chemical reactions


One thing missing in this article are the probabilities - the consequences of tire failure are bad (life and property damage) but the probability distribution at any given age is going to be very wide.. especially across the huge range of brands and designs. This is why everyone's experience is going to be different and why so many get away with using old tires. Another real world failure risk summary that rivals cam failures.

The article links to one summary of accelerated test development, apparently driven by regulatory efforts:

https://www.nhtsa.gov/DOT/NHTSA/NVS/...ac_SAE2010.pdf

In this summary, there is a chart that illustrates how much variation there is across a relatively small range of tested tires. I assume the markers are specific brands and/or tire designs:



The article doesn't touch on the material and design factors affecting the mechanisms but this chart certainly illustrates "not all tires are created equal".

Don't buy "Black X" tires, buy "Maroon Square" tires !!!

It would be interesting to know which brands put more R&D into this, but the bigger the company, the more liability exposure...

I'm now curious - are there DOT regulations regarding thermal aging of tires in service? Did the NHTSA efforts shared in the article result in testing standards that are now in use? If so, how did it all end up? What failure risk at what time at what temperature was determined acceptable?

[HWYSTR455]

Comment in one of the linked articles:

"Lower aspect ratios and higher speed ratings tend to correlate with longer life. This is probably due to less surface area in the air chamber and better construction, especially better inner liners."

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[kingbuzzo]

Sage advice...

I had 19y/o BFG's on my old T/A that I was trying to sell and didn't want to soak $ into tires then had the blowout on the lone highway.

Then just trying to FIND a replacement 295/50R15 in 2022 was a costly nitemare in itself.

Like the commercial says, the only thing between you and the road is yer tyres...



If you push the envelope on tire age, and accept the risks, I wish you luck. It costs a lot more than a set of tires to repair a quarter panel, or any panel for that matter.

In my experience(s), being cheap never ends well.

.[/QUOTE]

[Shiny]

Yes... risk is a combination of consequence, probability of occurrence, and ease of avoidance.

In this case, the consequence of a failure is easy to imagine and so bad as to dominate the assessment.

But the variation in the other factors is the hard part.

This is why I was wondering if there were DOT standards/regulations around thermo-chemical longevity.

It would also be interesting to know if any specific tire manufacturers try to distinguish themselves by offering improved resistance to aging. If so, they might actually share data or at least make claims... ??

[HWYSTR455]

Answer is simple. Money. They don't want to spend it because they want you to buy tires at shorter intervals. Profit.

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[Shiny]

Originally Posted by HWYSTR455

Answer is simple. Money. They don't want to spend it because they want you to buy tires at shorter intervals. Profit.

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It's always money, but tires wear out so manufacturers don't need to do anything to help sell replacements for the majority of their customers.

This feels like a risk for what is likely the small fraction of customers that don't drive enough to wear them out in 5 or 6 years. It may well be a reluctance to spend what it takes to keep them from degrading but my guess is only because 90% of the market wears them out before they fall apart. That would be an interesting bunch of statistics by itself.

Mike

[kingbuzzo]

Don't jinx us...they'll start a dreaded subscription service....wait, million $ idea 💡

[SRR]

Where you are at has a lot to do with tire life. I hardly ever wear out a tire they usually age out, ride like crap and get small cracks in the side walls here in sunny hot so. Cal. The tires on my 95 Jeep are almost five years old and are starting to show their age even with plenty of tread left. I only do short trips with it so I'll let them be for now. I refuse to put China made tires on my vehicles, they will ride hard and will be noisy in no time at all.

[Don 79 TA]

Q for the guys mounting and balancing now...
I guess the standard/typical machine is like the Hunter Road force balancer or similar right (say places like firestone, goodyear, discount tires, etc)
Is there an option to "fine" balance? I've heard of this, but also heard how much of a pain it can be, but the results are very impressive. you also need to capability of trimming the stick on weights or having various sizes
typically done for higher speed/higher performance times, from what i'm understanding.

When would you want a lug centric balance or a hub centric balance? and can these be "fine" balanced?
I'm asking in regards to the factory Honda Accord and Nissan Frontier tires/rims.
If i am not mistaken, Weld Wheels like my Draglites are supposed to be lug centric balanced.
Is this just a special adaptor or machine specific? Wouldn't your typical tire shops have this capability?

[mgarblik]

Lots of questions there to try and answer. The quality of an off the car balance had allot to do with the operator and the condition/age of the machine. Most computer balancers do not require calibration on a regular basis and many out there have not been checked in years unless the shop/operator notices lots of customer complaints. My Coats balancer is now 20 years old. I check calibration every 6 months or so. It does a self-test every time you power it up. The machine standard default is .25 OZ. This is because that's the smallest "standard" weight you can buy. It has an override button for "fine balance" this is .10 oz. You have to cut a 1/4 oz in half, generally a sticky weight to balance to zero. On old muscle cars with steel or rally wheels, if the tires are round, a balance within +- .25 oz will produce a very smooth result. Always remember, you can get a 0-0 balance with a square tire! So it will perform terrible with a perfect balance if out of round.

A road force balance adds a measure of "stiffness" to the equation. Even if a tire is round and balanced, there can be a stiffness variation in the tread or sidewall where the body plies or tread plies are overlapped and sewn. Also the seams can shift over time or just be poorly put together. On a Hunter Road force machine, a pressure arm applies about a 750 lb. force to the tread area and a sensor measures the deflection. This is road force. The software calculates an opposed force to smooth the results. It's a great feature but triples the cost of the machine. I find about 1 in 100 tires where road force is really needed to get a decent result so I have to pay to have it done. My machine doesn't have the feature.

Finally, the mounting on the machine does have an effect on results. Most balancers have a set of 4-5 cones that locate off the wheel center hole. The hole needs to be clean and the cones polished and checked for runnout. I check mine with a dial indicator and polish if they are nicked. They need to be +- .001. I also check the arbor for runnout. Cheap balancers have a 28mm shaft and bend easily with heavy wheels. The better balancers have a 40 mm shaft. They need .001 runnout or it needs new bearings or shaft. I doubt 10% of the tire stores EVER check the cones or shaft for runnout. They simply don't get paid to check anything and fix stuff only when it breaks.

Probably 95% of the stock wheels out there locate off the center hole so cones work. Hunter sells a set of high precision cones that are a set of 16 or 20 cones rather than 4. They are very expensive, around $2000.00. The multiple cones have less taper each and locate the wheel better. Some shops have them, some don't. For the 5% of racing wheels out there and some rare foreign cars that are lugcentric, a special adapter is needed. There are wheels out there that have NO CENTER HOLE. They of course would need to be located off the lug holes. Many racing wheels with shoulder lug nuts that pass through the wheel are lugcentric and will need to be balanced that way. The center hole is just there for convenience and not in the center of the wheel . As a very general rule, wheels that have conical lug seats are hub centric, but not always. It can get complicated. Hope this helps some. BTW, each machine manufacturer makes their own lugcentric adapters. Hunter and Coats units are over $2000.00 each. So not allot of shops have them. A large tire shop with 6 balancers may have 1 adapter and only one trusted employee is allowed to use it.

[Formulajones]

Everything I do here has been hub centric with one exception and that's balancing VW wheels. I have a lug centric adapter for that.

To eliminate all those potential fitment issues on my regular balancer and to also balance more than just the wheel, I also have (but haven't used in years) a Snap On balancer that does the wheel/tire assembly on the car, effectively balancing the hub/brake assembly in the process, all done never taking the wheel off the car.

I haven't seen these used in shops since the 80's. Usually seen in dealerships from what I remember. Some old timers may remember them.

[Don 79 TA]

thanks MG/FJ
I never heard of an on the car balancer, and good gawd do i remember doing some VW's that used Lug bolts.... talk about a pain in the butt sometimes

[mgarblik]

The on the car balancers were popular and effective, especially before computer balancers took over. They worked good on drum brake cars and ones with heavy wheel covers. Very dangerous to use, I hated teaching it. On the Hunter "Mexican Hat" machine, a friction adapter had to be attached to the wheel. They didn't stay on a chrome rally wheel very well like a Oldsmobile and could fly off at over 100 MPH and do major damage to the car and building and injure the operator. We had one fly off, go right through the glass bay door and out across 4 lanes of traffic coming to rest 200 ft. from the shop. Also the operator had to physically grab one of the four wheels on the Hat at speed to add weight and locate it to a position around the wheel. Never in a million years would a tool .like this be allowed to be sold and used today. But they did work well. The Stewart Warner strobe light balancer was a little safer to use. You didn't have to grab the wheel at 100 MPH. It used a magnetic pick-up placed on the lower ball joint. When the heavy spot on the tire/wheel reached 6 O clock position, it would induce a vibration into the sensor and flash a strobe light. Using the valve stem as a locator, you would aim the strobe at the wheel and try to get a flash of the strobe in relation to the valve stem. That's where you would place the weight. The hand held strobe also had an intensity meter that would sort of indicate how much weight was needed. It was hit or miss and usually took 4-5 spins to get the strobe to not light. Crude but effective. They were all 220 single phase machines. They worked great on 8-lug wheels with the huge, poorly balanced drums. You could NOT do the rear wheels on a limited slip car. Had to rotate to the front.