Question about tire company building bad tires. Are China Bombs built on purpose?

This as a long post but I wanted to share the type of questions i sometimes get.

" Good Morning' Roger. First, thank you for helping to dispel the misinformation about the care & feeding of consumer tires. 

    My training & work history is in the military & general aviation world. After a 24 year Air Force career and 17 years with Cessna in Wichita KS I've learned a great deal about tires. I've also had a near miss with some tires back in the day. 

   I had a set of Light Truck tires on our '84 Ford E350 15 passenger van. Not long after a tire story broke in the news, I looked at the tires installed on our van. No defects noticed, inflation correct, continue in service. 4 days later, while on the road to KC from Wichita I felt a vibration develop. I pulled to the shoulder and discovered a blister in the sidewalk of a rear tire. I installed the spare & the trip continued without incident.

    The following Monday I presented my defective tire to my local tire dealer. He was very apologetic for the defective tire. He replaced the remaining tires with a set of Bridgestones of comparable size. The whole incident was handled well.

   At the time I couldn't get the one tire that failed. I wanted to perform an autopsy of sorts. The dealer wasn't having any of that, which I understand. At the time the problem with the tires was explained to me that the sidewall de-lamination was caused by an incomplete cure process. The process was incomplete because a manager thought the vulcanizing process would run its course even after the tire was removed from the press. It was later reported that an inferior compound was used in the process. 

    So, I guess my question is, in the Light Truck tire incident, was it improper substitution of a material or a management failure in order to increase production that lead to the failures? Do Chinese made tires exhibit similar problems? Can the NTSB outlaw them? It's all above my pay scale. Just want to see some reliability in RV tires.

   I will continue to recommend your Blog to others in an effort to combat the misinformation surrounding tires. 

   Reply when you get time. It's a cold Sunday morning here & I'm working on the second cup of coffee. In this day & age, I don't do anything in a hurry & my upper arm is getting cold as my sleeve is rolled up waiting on my vaccine, but we'll survive. Stay safe, stay warm.

 

 

My answer:

Where / how did you get the information that the tire with the sidewall problem had some "inferior" compound?

Without a lot more data it's hard for me to pass judgment on tires made in the early 80's. I can however relate a personal experience that I have written about previously. This may shed some light on tire quality.

By late 2000 my primary job responsibility had become doing forensic tire inspection and analysis. I came across one almost new (weeks old) passenger tire with the steel in the belt having lost all adhesion to any rubber. There was only one tire and at the time no report of other similar tires. Many times single tire issues get set aside as a "single data point" is hard to establish any trend.  A few weeks later I was presented with two more tires with belt issues and upon conducting an autopsy discovered these tires had steel in one of the two belts, BUT NOT BOTH, having no adhesion to the rubber. The other belt had normal levels of adhesion. Recalling the single earlier tire I dug deeper.

Eventually, after some investigation and some test results from the chemistry lab, it was confirmed that a single batch of approximately 145 lbs of the rubber had been improperly labeled in the factory and built into about 150 tires. I notified the VP of Corporate QA and a recall was initiated with the permission of NHTSA (the agency like NTSB but dealing with automobiles, not commercial vehicles such as buses or airplanes). The recall covered some 6,000 tires as the effort required the recovery of all tires that were cured the week when the factory mistake was made.

Technically we knew that with only 145 lbs of rubber involved and the specific process used in that plant that a maximum of 150 tires could have been affected but since tires are recalled based on the DOT serial and all tires made in any one week carry the identical serial that was the only option.  It turns out that most of the tires were still in the warehouse which made completing that recall easier as many times even when recall notices are published a significant portion of the public does not pay attention.

Your suggestion that some inferior material was intentionally used in your LT tires just doesn't seem plausible as NHTSA would have ordered a recall of all suspect tires if there was data that supported the idea that some substandard material had been used.

In modern tire manufacturing, most rubber compounds are used in many different sizes and types of tires. I would say that the sidewall rubber in the Light Truck tire would probably have been used in most if not all LT tires being made at that time which would have involved millions of tires.

It is also true that tire store dealers do not get detailed training in tire forensics so sometimes they tend to simplify the explanation for a problem. When tires are "adjusted" and replaced however those tires are sent to be inspected, in detail, by engineers with the necessary training and experience. If manufacturing errors, as found in my example, are confirmed, appropriate action is taken as there are serious financial fines for knowingly allowing tires that do not pass DOT requirements to be sold or used.

All tires sold for highway use are certified by the tire manufacturer to be capable of passing the DOT test requirements and the data I have seen, including a number of tires made in China, shows that the tires meet the DOT requirements. The "China Bomb" concept is a combination of improper use and improper understanding of statistics. It is a known fact that a majority of tires on RV trailers are overloaded. Also, some 90+% of the tires applied to RV trailers were for a number of years were made in China. With these known facts is it any wonder that there were tire failures on RV trailers and that most of those failed tires had been made in China? Many people jumped to the incorrect conclusion that since very few tires failed on their passenger cars or pick-ups and that the tires on their cars and pick-ups were not made in China. That the China-made tires must somehow be "defective" even while never being able to identify any specific "defect".

A side issue. You mentioned a desire to "perform an autopsy of sorts" immediately raises the question in my mind of how and what you thought you would do when doing your first tire autopsy? I suggest you read these blog posts where I mention "Autopsy" and ask yourself if you would have noticed or been able to identify the evidence I pointed out in these examples. And if you had noticed the details do you think you would have reached the same conclusions I did?

Hope this gives you something to read and think about on a cold day in March.

 

##RVT990

 

Can you do a tire "Autopsy" at home?

 When you have a tire failure many people are only interested in replacing the tire as soon as possible. But there are others that want to understand the "why?" of the failure so they can take the steps necessary to avoid a re-occurrence of the problem for if you don't know the real basic reason for the failure any corrective action you might take may not actually "fix" the problem.

Think of a car not starting. If you jump to the conclusion that the reason for the non-start, is a bad battery when it really is the first signs of a failure of the starter motor or a failure of the ignition switch, the new battery will not "fix" the no start problem will it?

Now I am not saying that everyone needs to have the tools and skill to do the "autopsy" shown below but when I was working as a Forensic Tire Engineer I was expected to dig deep and to learn the real reason for a tire to fail. 

It is in my basic nature to be inquisitive, so when I was contacted by an RV owner who had what he thought was a tire about to fail I decided that I could help him learn and understand the "why" when he started asking questions as many engineers do.

The following is what we did and what we learned.

As you can see the tread is very round.

 

This is not normal for a steel belted radial tire.

John, the owner measured the OC of all 4 tires and found a big difference with one tire being an inch larger than the others.

Clearly something was different this tire.

After removing the tire from the rv and looking closely at the tire he noticed that one portion of the tread seemed to "bulge" outward.

 

His next step was to confirm the tire was no longer round.

 

 After de-mounting the tire and inspecting the interior he said he could not find any indication of failure. At that point John contacted me and after some back and forth I told him how to dissect the tire so he could ship the tread portion to me for a more detailed inspection.

You can see the work he had to do to get the tire tread area cut from the rest of the tire.

 

This was John's effort to

find the belt separation,

but he was not sucessful.

When I received the tread my experienced eye quickly found the location of the belt separation.

This level of effort on John's part was extraordinary but we got the evidence to prove a belt separation as the reason for the bulge in the tread area.

Now you don't need to go to all this effort as a simple "Free Spin" inspection as seen in this YouTube video will provide the evidence you would need to decide if it is time to replace your tires.

I have recommended that owners of RV trailers do a "Free Spin" inspection once a year or every 2,000 miles. This schedule might line up with when you inspect brakes or re-pack the wheel bearings so the Free Spin is not any additional effort and if you discover a wobble or bulge in your tire you know that it's probably time to replace it rather than wait for it to come apart on the side of the Interstate. 

A Tire Autopsy "Root Cause" Part 1

Many  people make statements about a tire "blowing out" or being defective but few post any facts about the real condition of the tire other than it came apart. There is a major difference between simply reporting a condition and providing information on the "Root Cause".
Examples of Conditions would be "the tread came off' or "tire lost air" or "tire went BOOM".
Examples of Root Cause might be "tire had a puncture" or "tire had an impact break" or "tire was run low and the sidewall had a flex failure". If you don't know the "WHY" of a tire failure then whatever actions were taken after the failure may or may not help to prevent a re-occurrence.

To help you understand this concept I want to take you through some real life examples. In many of these examples it was initially claimed that the subject tire was simply "defective" however as we review these examples I think you will ultimately agree that most tire failures occur because of some outside cause.

Here are three examples of damage done through the use of a high pressure power washer.

In each case someone claimed there was a defect built into the tire that caused a blister to form as seen in the pictures.

I know and proved that the damage was in fact caused by the use of a power washer as I did a quick cut tire examination (autopsy) to examine the layers of the sidewall. No internal contamination was observed.

A theory was formed and an experiment done to confirm or refute the theory. A tire that was sound was selected and using a pressure washer similar to what any of us could buy at a big box hardware store, we were was able to duplicate this damage.

Sidewall Impact Breaks occur under a combination of variables that have a very complex interaction. These include speed, load, inflation, shape and size of the item impacting the tire, angle of impact and even the condition of the shock absorbers. Change one or more of these and you may avoid the damage.

What usually happens is the pot hole or road debris is hit but if the tire doesn't immediately fail the incident is forgotten. Miles later the now damaged and weakened sidewall ruptures with no advance warning. Even if you have a TPMS you will probably get only a few seconds advance warning as the now hot rubber will rupture very quickly and the tire will many times shred which destroys the evidence.

Sometimes the sidewall bulge is observed before the sidewall ruptures. The inspection of tires with this body ply damage allows us to identify the sequense of events. In fact if you attend one of my tire seminars I relate the story of my then fiance and her experience of traveling over 17 miles after the impact before the tire ruptured.

Next time I will cover Belt Detachments

                      and Punctures

Autopsy of a failed tire

I continue to see posts on various RV forums saying "I had a blowout on my tire. I checked the inflation every day and I didn't hit anything. It must be because it was a (fill in the brand)  or  because it was made in (fill in the location). I'll never buy that brand or tires made in that location again cuz they are junk."

If you are a follower of this blog you have seen this topic discussed previously but clearly there are folks out there who just do not want to be confused with evidence that doesn't support their pre-concieved notion of why tires fail.

Lets follow an "autopsy" of a failed tire and see if we can improve people's understanding of how to "read" a  failed tire so we have a better idea of the real reason it failed. If we don't properly understand the "WHY" then we probably will not take the appropriate action to prevent a re-occurrence.

 Here we note the size as 8-14.5. This is a low platform trailer tire. Many times used on Mobile Homes or construction equipment trailers. It is a bias construction and we can see the body ply at an angle.







We see this tire is a Load Range F (12 Ply rating) tire.
 


rated to carry  2835# at 100psi cold.

Looking at the tread we see the tire "looks" great.
 






As we continue to read the tire sidewall we see it was made in Thailand..
 




Now for some, that is sufficient. They say it wasn't made in the USA so it is a piece of junk. Lets continue and see if they are correct in their analysis.


 
The DOT date is 2812 so since this tire failed mid June 2013 or about 2613 the tire is only 1 year old and clearly since it came from Thailand there were probably 3 or 4 months for shipping and handling in a warehouse. Clearly the tire age is not the problem.

The first two characters of the DOT"2B" can be translated using out decoder web site  and we learn the tire was made by Deestone Ltd in Samutsakom, Thailand.

Continuing on we see the tire is Nylon body which would be consistent with a lower cost, bias, heavy duty construction.

Now we get to the interesting part. Looking at the actual area of the failure.
 In the picture at the top of this post you can see that both sidewalls have significant damage.

 As we look at the area of the tire that actually failed we see frayed cord.  This is what Nylon and Polyester look like when they fail in tension. Looking closer we see that not all cords are frayed.


These three cords have the look we see when we cut Nylon rope and fuse the ends with a lighter.


Warning Technical Information to follow:  Nylon and Polyester both melt in the range of 395°F to 495°F depending on the treatment and exact material involved. These materials also lose about half their strength when heated to over 300°F.


Looking even closer at those cords it is clear the ends are not frayed but fused. So we now have the physical evidence that parts of this tire saw temperatures approaching or exceeding 400°F. The only way to generate that kind of temperature is with rapid, extreme flexing.
 We see rapid flexing at highway speeds. We see extreme flexing when a tire looses say 50% or more of its proper inflation.

The heat in a tire comes from the bending of the cord material and radiates outward to the cooler surface.  It is illogical to think that only a few cords somehow flex enough to see high temperature and if we look closely all around the area of the most damage there are a number of cords showing similar heat damage.

So we now have physical evidence that proves operation at highway speed for a number of miles while the tire is significantly under-inflated.

Knowing this, I think you can understand that there was probably some other cause such as a leaking valve or puncture or cut of the tire that allowed the air to leak out over time. If the tire had in fact been properly inflated we would not see the 360° circumferential flexing and signs of high heat.

How do we avoid this type of failure?  Will changing the brand prevent air loss?  Will buying tires made in a different country prevent them from getting too hot when over flexed? Clearly neither of these "fixes" will prevent a reoccurance of this type of failure.

I would suggest a TPMS could provide warning if there is an air leak. That warning might be early enough to allow the driver to stop before the tire fails and maybe even before the tire is significantly damaged.

BOTTOM LINE
I would say that 95+% of tires I have seen with this type of "blowout" failure were in fact Run Low Flex failures. Having inspected many thousands of tires in my 40 years as a tire engineer, I have accumulated enough experience to be able to observe and find the physical proof of high heat damage similar to what we see here. Many times I can find and identify this proof in less than a 30 seconds. It's easy once you know what to look for.

Hopefully the next time you meet someone that says "I just had a Blowout" you will be able to identify the evidence that points to a run low flex so the person learns they need to know why the tire lost air. If it were say a leaking valve it certainly will do them no good to buy a new tire and mount it only to have it suffer the same fate.

Tire Autopsies - Run Low Flex Failure and Impact break

 I thought it might help to show a few examples of what was observed while doing a "Tire Autopsy".

A tire would be received with a complaint letter. The letter might say something like " I was driving down Route 66 at 55 mph when suddenly I had a blowout. I wasn't speeding and had checked the inflation just that morning. What is wrong with your tires? There must have been a defect.

The tire looked like this. 

 

 

 

 

 

 

Another view 

On close inspection I found what looked like a hole in the upper sidewall where the

rubber had been worn away.

 

 

 

 

 

 Using a bent paper clip,

 

 

I was able to confirm the hole

 

and looking inside we can see where the puncturing item

went.

Note a bent paper clip will fold at the bend if you try

 and push it through a tire sidewall, but if there is a

 hole the paper clip can follow the hole.

For this case I provided the above information and pictures.

====================================

Another complaint involve a bulge in the tire sidewall.

 The location was marked by the tire dealer.

On the inside we see a lump

We can also see a dark curved line where the tire

had extra bending.

By cutting away the rubber from the inside of the tire,

down to the body cord we can now see the broken

cords from the impact.

I trust that after seeing these examples you have learned that

sometimes additional examination is required to find and 

confirm the actual failure.

After doing hundreds of similar examinations it allows the

experienced examiner to quickly identify that the reason for

 a tire failure was not some design or manufacturing "Defect",

but the result of external causes.

More like thin in future posts.

How much Reserve Load or "Headroom" is enough?

Following an RV forum discussion on How much extra load capacity or "Reserve Load" or "Head Room" is enough. Some folks had moved from LR-C to LR-D  others to LR-G but were concerned about running the tire sidewall pressure as it would be too hard on the trailer.

There was also some confusion about the "Maximum" allowable inflation.  I said:
"The inflation on a tire sidewall is the MINIMUM inflation pressure needed to support the MAXIMUM load (also molded o the tire sidewall).
There is a sound scientific reason to run higher inflation when running tires on multi-axle trailers. It is called "Interply Shear". This force is what can result in belt/tread separations. I have covered this in detail along with references to technical papers on the topic.
IMO you need a minimum of 15% "head-room" of load capacity over the measured load of the heavier end of an axle. (CAT scale only gives the total on an axle and very few RVs have 50/50 load split. Some folks have discovered unbalance of 500 to 1,000#)
Most cars come with 20% to 40% tire load capacity headroom. I run 25% on my Class-C."
Which resulted in this reply:
"So if a given pressure (below the tires maximum) still provides the necessary headroom over the measured load, it's okay to run it, correct? Or am I not understanding something? "

This leads me to respond:
"I wish it were that simple but all radial tires have the Interply Shear force. It's a question of how much "tire life" is being "used up". The force results in microscopic cracks forming between the two steel belts at the outer edge. Once cracks form they do not repair themselves but can only grow.
No good tool or math model can turn Shear Force into Miles of tire life is "consumed" as there are just too many variables.
Finite Element models simply indicate that higher inflation can result in lower shear force every time you turn a corner or every time a tire completes a revolution. 
About the best you can do is to do a close visual inspection (Free Spin) to look for signs or out of round or side to side runout which are strong indicators of internal structural tears. I have a video and pictures of the autopsy I did on a tire where you can see the separations running across 50% to 70% of the tread width. This large separation might run a thousand miles or under certain circumstances might fail tomorrow.
Think of it like your Blood Pressure. Higher is worse. So the question is at what number can you expect to have a fatal attack?
If you consult your owner's manual you will see a suggestion that 3 to 5 years is the max expected life but obviously someone that runs at or above Max Load and above 65 mph and drives 4,000 mi a year is more likely to suffer a failure than someone that only drives 2,000 mi, never faster than 62 and at only 80% of tire load capacity.
Moving up one Load Range C>D or D>E can probably expect longer tire life if they also go from 50 to 65 or 65 to 80 psi. Going to LR-G in a Commercial grade all-steel tire should result in longer life even if you don't run 110psi.
Since load capacity is shown in the Load/Infl tables then I would suggest trying to get to 20 to 25% Reserve Load would be a good move. You still need to watch max speed and minimize sharp turns (as seen when backing) and of course, do a good free spin inspection once a year or once every 2,000 mi whichever comes first. Plus run a TPMS to confirm you never run lower pressure than your goal."

I realize this is a long winded post but hopefully, you can think about the ideas and concepts we are discussing.  Easy questions do not always get simple answers, Especially when talking about a complex topic.

##RVT888

 

"Dry Rot" is a misnomer regarding tires

Read this on an RV trailer forum, but most of the info applies to all types of tires.

"My understanding is that there seems to be a belief or a known orthodoxy that despite external appearances, the inside could rot out and that tires that appear all fine and dandy on the outside, after that long are not on the inside?

I believe the only "proof of concept" is common anecdotal experience:

People have owned tires that appear fine that are "old yet all seems fine", and they experience unanticipated tread separation and such....several anecdotes to the point of it being a "common wisdom" best I can tell.

Beyond that, I have not seen a "more objective" verification of this...in my mind, after the death of such an "old yet otherwise in good shape and used properly" tire, an autopsy of that tire could show evidence of this "rotting from the inside"....I am not sure anyone has posted details about what that would look like (beside unexplained otherwise tread separation)?

Absence of such "more objective review", I am very very inclined to accept the common wisdom or orthodoxy on this matter until clearly proven otherwise as the cost of being wrong is potentially massive comparatively!!!!!!!!! Many many posts on this site have expressed huge regret about pushing past such "widely accepted advice"

My response to the above:
I did "tire autopsies" for decades before retiring. I have even posted pictures on my blog and have over 30 posts that have "Failure" as a label. Best advice I can give is to read and review the information on my blog. Listen to the only two (to my knowledge) actual tire engineers on RV forums: myself and CapriRacer.

"Dry Rot" is a misnomer. Rubber is a long chain polymer. The chemistry is such that the polymeric chains break down over time. The rate the chains break is related to heat and other energy (UV) input. Nothing is actually "drying out" or "rotting" in the common understanding of the word. Sidewall cracking (dry rot) is just a symptom that suggests the internal rubber compounds have probably lost some of their elasticity, which increases the potential for cracking, which may lead to separation.

There is no single answer to why some people have longer tire life than others except for the fact that some operate their tires at higher temperatures (load, speed and inflation plus ambient temperature) than other people.

Any tire can fail with a Low Inflation sidewall flex failure or "Blowout". Radial tires in trailer application are exposed to significantly higher Interply Shear forces due to suspension design that the tires on the tow vehicle - See my post on Interply Shear.

While operating a tire can help the "Anti-Oxidants" or AO's migrate to the surface, simply driving the tire is not IMO an efficient or effective thing to do, especially when we consider that cleaning of the tire sidewall, which will remove the AO's, can result in more harm that any driving around can prevent.

How many of you have bothered to make load and inflation adjustments necessary for driving your ST type tires any faster than 65mph?

Do you even know the actual loads on your trailer tires?

How many do an annual "free spin" inspection of your trailer tires?

How many are running TPMS (tire pressure monitoring systems) so you get warned when you drop down to the minimum inflation needed to support the measured tire load?

If you feel that checking your pressure with a hand gauge is sufficient, do you make that check every 10 to 15 minutes of operation? If you have a tire leaking air you can destroy it in just a few miles, so the fact you checked the air 4 hours prior to the failure is of no importance.

Sorry for the rant but the FACTS are out there. It takes a little effort to drastically reduce the potential for premature tire failure. There is no magic snake oil spray that will make your tires last 20 years. There are steps that you can take to get 5+ years of life in trailer application and 7+ in motorhome and tow vehicle application.

##RVT798

"I inspected my tires but still had a failure"

Read this on an RV trailer forum:

"Checked the air in all 4 tires and inspected them before we pulled out. We made it 20 miles from the house when the first tire let go. The tire service center and I both checked the remaining 3 and the spare. They had the correct air pressure and no signs of any issues. We made about 15 miles down the road and the second 1 blew out -- 2 roadside assistance calls and 2 insurance claims. I am not happy with dynamic tire or (RV trailer company name) at the moment."

I offered the following comment:

Sounds like the "inspections" being done are not sufficiently detailed. A "proper and complete" inspection doesn't consist of checking the outside sidewall and most of the tread for % tread wear. A LOT more is required if you want to improve your chances of finding the early signs and indications of impending tire failure.

In this blog, I have previously covered what I would consider a thorough inspection with example of what a failing tire looks like externally, and then I did an autopsy to show the actual condition of the subject tire. Note that the person making the video felt the tire had failed and cut the tire looking for the belt separation but even though he has an engineering and mechanical background, he failed to properly identify the location of the failure. IMO this was because he simply had not had enough experience in tire forensics, as you probably have to do a minimum of a few dozen autopsies before you can easily and quickly know where to do the cutting -- and that would be what is needed to find a large separation as seen in the subject tire. Smaller issues are harder to find and take a more experienced eye.

The free spin can be sufficient to establish that the subject tire is in the process of failing and should not be driven on.

Today it is popular in politics to complain about "the elite" and to disdain experience, but I believe that there are many fields where actual experience is necessary if you want competent results.

Very few tire service people have been given the opportunity to do investigative-level tire inspection, as their job normally doesn't require issuing a detailed report that identified the root cause of a tire failure. This not the tire tech's fault nor is it the fault of the tire store owner. You might liken this to the store clerk at a CVS or Walgreen pharmacy. They are simply not fully knowledgeable in the interaction of medications, which is why a Pharmacist is the person responsible to fill prescriptions, but I would not trust a Pharmacist to do surgery.

Sometimes competence only comes with experience.



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Tire Failure because "Made in xxxxx"

In my training class for tire engineers and technicians, a concept I feel is important is discovering the "Root Cause" or real reason for the failure. There is difference between reporting or simply stating the condition of a tire such as "a Blowout" and the reason for the condition. If you don't understand the underlying reason for the tire's condition or what initiated the series of events that led to the failure, then the corrective action you take, may not prevent another failure.

If we are confronted with a tire that looks like this
many would simply say "we had a blowout". If they then read the information on the tire sidewall that says "Made in xxxxx"  or if they read the DOT serial and used the information on THIS website to learn where the manufacturing plant was located they might simply claim the tire failed because it was made in country xyz. They then simply jump to the conclusion that the way to prevent having a similar failure in the future would be to only buy tires not made in the same country the failed tire was from. They might feel better but in all probability they will not have taken the appropriate action to lessen the chance of having another failure as the country of origin in itself, is no more likely to have "caused" the failure than would the fact that the tire plant was painted blue rather than green.

Lets step back and look for physical evidence for the real reason or "Root Cause" for the failure. A simple trick is to ask WHY? at least 5 times. Here is how it works in the case of this failure.
1. Why did the tire fail? Answers might be the sidewall shredded or the tread and belts came off or there is a large bulge in the sidewall or because there is a nail or other puncturing object in it etc. Each of these answers would generate a different 2nd question
2. Why did the sidewall shred? Answers might be: Possibly hit a pot hole or tire was driven on after it lost air.
3. Why can you know if you drove on it after it lost air? Answer It would have melted body cord or fatigued steel body cord
4. Why did you drive on the tire after it lost air?  Answer might be: I didn't know it was leaking
5. Why did the tire leak? or Why didn't you know the tire had lost air?  Answer might be: The valve failed or I had no Tire Pressure Monitor System.
Now you have enough information to take the appropriate action as simply changing brands of tires will not stop the valve from leaking or give you warning of an air loss due to puncture in the future.

Now to help you out with understanding what evidence can help you ask the correct questions I will offer a few examples of various conditions.

Tire puncture large and obvious

Tire puncture small and hard to find

Melted polyester body cord only occurs when tire structure temperature exceeds 375° F

Steel body ply fatigues along the line of greatest bending sometimes resulting in a "zipper"

Steel fails (think paper clip) when bent back and forth more than it was designed to for many cycles. You can see this "necking" with a low level magnifying glass.

I hope this helps you understand that it is very difficult to stand back 10 feet and look at a tire and know why it really failed. I also hope that you have a better appreciation for the fact that if you don't investigate and learn the real reason for the failure simply changing the tire brand may not prevent another occurrence.

Bottom Line
If you have a failure you need to preserve as much of the evidence as possible so either you or the tire dealer you work with can do a more thorough "autopsy" to learn the real reason for the failure. If the tire is under warranty, the dealer or manufacturer will want to be able to examine the failed tire. It is unrealistic to expect compensation for a failed tire without you being able to provide the evidence of the failure. The major manufacturers have teams of engineers who's job it is is to inspect failed tires so appropriate action can be taken. This is why I suggest that you buy your tires from a large tire company with thousands of stores rather than buy the cheapest tire you can find at "Billy-Jo-Bob's Bate Shop & Cheap Tire Emporium" .

Are IR guns good for detecting low inflation in tires?

 Comment of Facebook about RV tires

"I carry a heat gun with me. When I stop I check all tires. If one is a lot hotter than the rest I have a problem."

and another

"A cheap harbor freight gun is a good investment. We carry two when I tow my boat to the keys. Each stop my buddy and I have a gun in each door. We each shoot all four wheels then compare noted about what we got as far as readings."

 My response:

As a tire engineer I can advise that IR guns are OK for checking the temperature of metal items such as wheels, hubs or brake drums that conduct heat but rubber is an insulator and very poor conductor of heat so no IR hand gun I know of can detect a meaningful temperature at a rest stop as it isn't the average temperature of a tire that can result in a failure but a spot, maybe smaller than a quarter that you have to worry about. What testing have you done to learn that exact spot over the entire surface of your tires?

The hottest location (most likely to fail or cause problems is also about 1/4" deep inside the structure). Heat is the result of running overloaded or under-inflated. Scale measurement is the only reliable way to know if you are overloaded. Pressure readings are the only reliable way for a consumer to know if they are running under-inflated. You can pick up a nail or cut or have a leaking valve and be underinflated within a few minutes and have a failure a few miles later. The tire I covered in my detailed post where I did a visual "Autopsy"reportedly had it's air pressure checked just 50 miles before the catastrophic "Blowout" run low flex failure. A leaking valve core from improper seating is one possible reason for the air loss the led to the failure. A TPMS is the only reliable way to know the actual running pressure unless you stop every 5 to 10 minutes and check with a gauge and confirm your valve core has properly sealed after you check the pressure. A TPMS can even sometimes warn of brake or bearing problems because the heat is transferred through the metal parts to the metal base of the TPM sensor. 

I do think these low cost temperature sensors have other uses such as checking the temperature of your furnace output or confirming the electrical connections in your 'fuse box" are not getting  overheated. Even the heating element in you absorption refrigerator can be checked. I did use my IR gun to check the surface temperature of my tires when I did my test on tire covers but running tires have a wide range of temperatures as seen here with the output from a $10,000 IR camera. Note the wide range of operating temperatures (80F to 130F) in close proximity ( 0.10") when the passenger tire was run with 27 psi.

 
It only takes a few seconds for the surface temperature to drop significantly which would be less time than it takes you to come to a stop in a rest area so your readings would not reflect the important temperatures near the tire hot spot.

##RVT1026

How good are Chinese tires?

While this seems to be a reasonable question to those who do not believe it is possible for good quality products to be made in China, I could just as easily ask: How good are the tires made in Japan? or Brazil? or France? What about tires made in South Carolina? or Tennessee? or Nova Scotia? Etc.?

Some research indicated that Bridgestone, Michelin and Goodyear produce tires in more than 50 countries. Each of these companies has production in China. With more than 340 tire plants involved worldwide, just how reasonable is it to think that one country has cornered the market on poor quality?

Quality is a function of corporate philosophy not geography. Having worked as both a trainer and quality auditor in the tire industry, I can say from personal observation that I have never seen a situation where the poor quality in a product or process could have the root cause traced to the geographic location. I have also done detailed examination of tires made by a smaller manufacturer in China and found that they met all the performance requirements required for sale in the USA.

All tires sold for use on public highways in the US are required to be certified by the manufacturer to be capable of meeting the quality and safety requirements as published by the National Highway Traffic Safety Administration which is a part of the US Department of Transportation. These requirements are very detailed and cover many test and conditions all tires must meet at a minimum. The penalty for selling a tire that does not meet these requirements is very significant. You can read the details if you are so inclined, with sections 109, 110, 119, 120, 138 and 139 being most appropriate for those interested in tires.

TO GIVE YOU AN IDEA of how seriously these quality standards are taken by a company with a real quality philosophy, I would like to give you an example. Before I retired, one of my primary duties was to investigate and determine the real reason certain tires failed to deliver the service expected by the customer. I would be asked to basically do an autopsy and issue a detailed engineering report with supporting documentation such as photos and lab data when appropriate. My report had to be sufficiently detailed and documented to be able to satisfy other engineers and technical authorities that my conclusion were accepted as the most likely reason and that no questions remained.

During one such examination, I discovered that there had been a problem during manufacturing of one specific size and type tire. I was able to trace the root cause to the use of one container of materials that had been mislabeled and incorrectly used in regular production tires. The result of this mix-up was that some of the rubber did not provide the proper level of adhesion, which resulted in part of the tire not properly curing. As part of the investigation I was able to determine that 149 tires had been made with this improper material. I located an identification mark on the subject tires which would have allowed more than 95 percent of the 149 tires to be identified and replaced. The corporate head of quality decided that we needed to be 100 percent certain that no tires remained in the hands of the public, so he ordered the entire week’s production of that size and type tire be recalled and replaced. This cost the company more than 3,500 tires to be replaced at no cost to the customers and all 3,500 tires were ordered scrapped just to be sure not a single tire with the problem remained on the highway. You may be interested to know that the tires were not manufactured in the USA and not all 149 would have been sold in the USA, but the commitment to quality was sufficient to make this decision a relatively easy one.

Now you may ask how do you find out which tire companies have this kind of commitment to quality. One thing you could do is to contact the tire manufacturer and ask if they are ISO certified to quality standards such as the older QS9000 standard or more current TS16949.

Meeting this standard is a requirement of the “Detroit Big Three” and I believe some large heavy truck manufacturers. I also believe that if a company supplies tires under these standards they are more likely to apply most of the requirements to all their production.
NOTE These Quality Standards are in addition to the DOT Regulations.

If the tire you are considering is made by a company that does not supply to “Detroit” you will have to do some other investigation. You can search for information on recalls here.

If you have a tire failure that is not attributable to overload, under-inflation, puncture or road hazard you should file a report here

If people do not file a report the DOT has no way of knowing that a tire failed to meet the requirements.

“I had a Blowout”

That’s an all too often statement heard from RV owners.

According to some data a significant portion of RV owners have experienced a tire failure in the past two years. All too often the tire is blamed but my experience from examining thousands of “tire failures” is that the vast majority of these failures can be traced to the service conditions and not some so-called defective tire. Let’s look at a few examples.

Here we see an LT type tire that is now in two pieces







This picture shows the classical “Three piece Flex Failure”. I bet you see a tread ring like this almost every day in your travels.




This tire was one I did an “autopsy” on. Looking at the “broken edge of the sidewall we can see hard body ply cord.





Taking a microscopic look at just one end we easily see the fused cord.








This is much like what we have all seen when we cut Nylon or Poly rope and then melt the end with a match. Click on the picture for a better view.
It takes excessive flexing at a high rate to generate sufficient heat to melt the cord like this.
This Body Ply cord melts at approximately 495°F. I usually say the tire was operated at less than 20% of the proper inflation and at normal highway speeds to generate this level of heat.

Before you say “Ya but I have steel body ply so it’ can’t melt”, just think about how easy it is to break a paper-clip by flexing it back and forth.




Here you are looking through the hole in the sidewall of a 22.5 size tire that ran low at highway speeds but lost it’s air because of a bad valve leak.


So was this “blowout” the fault of the tire? Or was there some reason the tire lost most of its air pressure which let the tire flex excessively? I say that based on a majority of tires I have examined, "Blowouts" like these are really Sidewall Flex failures from being operated at highway speed while the tire has lost 3/4ths of it's inflation



Next time you see a tread ring by the side of the road or hear someone say “I had a blowout” you now know one of the probable causes.

Finally, You might ask if there is a way to prevent a sidewall flex failure. I believe that if you have a properly functioning TPMS it should warn you before the tire has lost 20% of it's air. If still inflated to this level it isn't considered officially "flat" and I have never seen a tire that can generate the heat necessary to fail a sidewall if it hasn't been run "flat". If you can set your TPMS to warn you if you either loose 10% of your air pressure or it sees a temperature over 170°F in most cases you will have sufficient warning to avoid this type of catistrophic failure.

Understanding Tire Failure

Yes, when a tire fails there is almost always evidence left behind that points to the Root Cause. I have shown this in tire "autopsy" posts on my blog.

Some "causes" are easy to see or understand:
Punctures, cuts and external damage from hitting potholes or other "road trash" can lead to leaking air (fast or slow) or in some cases broken body cord (see my blog post on sidewall bulges).

"Blowouts" with sidewall flex failures are most likely the result of air leak, not just low air pressure due to poor maintenance. The leak could be caused by puncture, cut, leaking valve, cracked wheel or the like.


Other failure modes are harder to detect, such as:

Belt separations come from long-term heating of the tire belt/body interface. This heating comes from a combination of insufficient air pressure for the load and excessive speed.

Now while separations may be harder to detect, many can be found if a little effort is made by the person doing the tire inspection.

I previously published a video showing one way to "measure" a defect.

Sometimes you don't need to "spin" or rotate the tire but just get a good look at it and roll it across the floor for a full revolution as one part may look OK while another portion clearly would only look straight to a drunk.

If any of your tires look like the above, I would bet $$ that they had a belt separation similar to what is seen here.

Driving on a tire in this condition is simply asking for trouble as it could come apart when you least expect it as you drive down the road.

As we move out of Winter and you "DE-Winterize" your RV, especially trailers, Please take the time to do a thorough tire inspection.  Spin or off-the-vehicle inspection is much better than a stationary on-the-vehicle "Look At".




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