What is a tire "Blowout"

[Tireman9]

The term "Blowout" is used quite a lot on RV forums. The problem is that to many people, any tire failure for any reason is a 'Blowout".

I recently posted an explanation along with pictures of the physical evidence used by tire engineers to learn the cause of a catastrophic tire failure. If you don't understand why the failure occurred your corrective actions may not prevent a re-occurrence.

The post in question was done in the 5th Wheel thread but the facts apply to all types of tires so I am posting the link here as some may not visit the 5th wheel threads as they don't own such a unit.

If a tire suffers a failure in the sidewall that extends around the tire many times it is what tire engineers call a "Run Low Flex Failure" or sidewall blowout, which occurs when a tire looses most of its air over a period of a few minutes while traveling at highway speeds.

Hope this is helpful.

[mel s]

IMO a 'blowout" is when a tire losses all of it's air with a bang.
(Any other air loss is a "leak").

[BFlinn181]

I'd think a blowout is a rapid loss of tire integrity. In a dual tire or trailer, a slow leak or puncture might become a rapid loss of tire integrity before the driver realizes it has happened.

[wa8yxm]

To me a slow lead that leave you feeling low when you check it is a "Flat Tire"

A Blow out is sudden dedcompression of the tire.. may be accomponied by a lout BANG. if it is a 60 PSI Bicycle tire it will sound like a rifle shot.

[Tireman9]

I understand your comments but the variety of definitions points out the problem.

If I were to have the following sequence of events occur what would be the appropriate action to prevent to problem from happening again?

Assume proper inflation to be 60 psi and I am traveling down the highway at 58 to 63 mph (speed limit is posted as 65.
The tire picks up a nail and air start leaking out. Five minutes later the pressure is down to 15 psi and the sidewall temperature ranges from 350F to 450F+. The body cord has lost 70% to 90% of its strength so a tear occurs in the mid sidewall. The remaining air escapes in less than one second and the tire is now in shreds as the driver looks for a place to pull off the road.

As far as the driver knows the tire was fully inflated up to the moment when all the remaining air escaped. While rapid air loss from 15 psi to zero is not as violent as from 60 psi, if the driver is not expecting it it will still seem like a big explosion as the RV also will be shaking violently.

If the driver simply looked at the tire and discovered it was made in Indiana he might incorrectly blame the poor workmanship in the tire for the failure, so simply changing to tires made in Canada would have no affect on the outcome of the tire leak,

The reality is that the high temperature leaves physical evidence that establishes the fact that the tire was run at highway speed while extremely under-iniflated.

The proper and informative term to use is Run Low Flex Failure.

The definition of a loss of 20% of the inflation air being a "flat tire" is to establish a point where driving on the tire would be doing structural damage.

Using incorrect terminology can be very misleading.

If we were to look at a person that had died due to claimed "heart failure", what might you suggest to prevent a recurrence?
Maybe he should have exercised more or paid more attention to his diet.

But what if the "heart failure" had been caused by a 45 cal bullet?

See how incorrect reporting of the condition can lead to an incorrect diagnosis with the potential of the "corrective action" really being of no benefit at all.

[BFlinn181]

Seems to me all you're doing is making a case for a TPM system. Regardless if it deflates slowly to 15 psi or immediately goes from 60 psi to 0, as a driver my reactions need to be the same. If it's a front tire, hit the accelerator to maintain control and pull over with no sudden, violent steering.

The question on whether it was a slow leak - failure, or a blow out failure, that can be dealt with by the tire manufacturer and/or insurance. My immediate concern is getting stopped safely, out of traffic.

[WeatherTodd]

Originally Posted by Tireman9

...
The proper and informative term to use is Run Low Flex Failure.

The definition of a loss of 20% of the inflation air being a "flat tire" is to establish a point where driving on the tire would be doing structural damage.

Using incorrect terminology can be very misleading.

If we were to look at a person that had died due to claimed "heart failure", what might you suggest to prevent a recurrence?
Maybe he should have exercised more or paid more attention to his diet.

But what if the "heart failure" had been caused by a 45 cal bullet?

See how incorrect reporting of the condition can lead to an incorrect diagnosis with the potential of the "corrective action" really being of no benefit at all.

um when the air goes from 150, 100, 75 or 40 to zero in an instant...thats a blow out. If you want to play semantics... have at it.

Ive yet to meet any sane person call a fatal gunshot to a heart as "heart failure". However you can start your campaign on correct terminology with newscasts... they like to use incorrect terms.

[wa8yxm]

In that example of a slow lead leading to a low tire and sudden explosive decompression of the remaining pressure>>> That is a blowout.

If you look at your tire and due to a slow leak it is low: Low tire
If you look at it and it's flat: Flat tire
IF you are driving and there is a SUDDEN LOSS of pressure: Blow out

Does not matter if it was low before the blow. it is a blowout.

[Gary RVRoamer]

Despite how tire engineers may need to split hairs when determining the cause of failures, I think any vehicle driver (or passenger) is going to call a sudden and total loss of tire air a "blowout". It's certainly true the problem may have begun a few minutes, or even a few days, before hand, but if it went unnoticed until the catastrophic air loss occurred, it's till a "blow out" in any layman's view. I don't think any educational campaign is gonna change that.

What we may be able to do is to educate motorists that blowouts can have several different causes and many of them begin well before the big bank happens. Maybe we can also convince them that few blowouts have much do with the tire brand or design, or even road hazards, and that a lot them are related to pressure, load and speed factors.

[Ray,IN]

Thanks for the information and education Bob. I think I read that on your blog too. Your knowledge and experience is of value to irv2.com members and guests.

[IC2]

Ahhhh, I really love engineering terms (best known as CYA). No disrespect to the OP as his set of terms are different then most of us have for a tire failure. This thread reminded me of a certain situation where my company sent out warning plates to be attached to the turbine compartment doors of a particular very large size gas turbine and is a warning that 'sudden over pressurization' might cause those several hundred pound pieces to become detached and cause grievous harm to ones body, even death. That was penned by engineers and of course needed to be endorsed by our fine lawyers.

This is the opposite in that a sudden air loss by a tire is a DEpressuization and what is known as a blowout to most of us. That sudden depressurization can also cause grievous harm to life, limb and/or property.

Thanks Tireman. Your information was a fine description of what really happens in a 'sudden' tire failure

[Tireman9]

Originally Posted by BFlinn181

Seems to me all you're doing is making a case for a TPM system. Regardless if it deflates slowly to 15 psi or immediately goes from 60 psi to 0, as a driver my reactions need to be the same. If it's a front tire, hit the accelerator to maintain control and pull over with no sudden, violent steering.

The question on whether it was a slow leak - failure, or a blow out failure, that can be dealt with by the tire manufacturer and/or insurance. My immediate concern is getting stopped safely, out of traffic.

The difference between having a slow leak or some freak occurrence when the tire goes from 100% inflated to zero in an explosive loss of air is that with a slow leak the driver is given the opportunity to smoothly and safely pull over to a safe location and stop. With sufficient advance warning this might give you a couple of minutes to find the safe location in the next mile. If this is the case and the driver has stopped before the tire is damaged there is a good chance the tire could be saved $$ with a proper repair and of course there would be no coach damage $$$$ to contend with. With the instantaneous air loss there is no time to react and we all have to hope the driver can maintain control of the vehicle and there is a place to safely pull off the road in the next couple hundred feet.

RE your corrective action and the insurance co. I too often read about people's plans to avoid a recurrence but seldom hear then express an understanding of the "why" the failure occurred in the first place. This kind of is like the saying "Those that fail to learn from history are condemned to re-live it. "
If we are talking about a tire failure it menas "Those that fail to learn the real cause of the failure are condemned to re-live it. "

[Tireman9]

Originally Posted by IC2

Ahhhh, I really love engineering terms (best known as CYA). No disrespect to the OP as his set of terms are different then most of us have for a tire failure. This thread reminded me of a certain situation where my company sent out warning plates to be attached to the turbine compartment doors of a particular very large size gas turbine and is a warning that 'sudden over pressurization' might cause those several hundred pound pieces to become detached and cause grievous harm to ones body, even death. That was penned by engineers and of course needed to be endorsed by our fine lawyers.

PS were the pictures seen in the link of the first post of any value? Need more examples?

This is the opposite in that a sudden air loss by a tire is a DEpressuization and what is known as a blowout to most of us. That sudden depressurization can also cause grievous harm to life, limb and/or property.

Thanks Tireman. Your information was a fine description of what really happens in a 'sudden' tire failure

Thanks, I think
"Sudden" is what the driver feels when the first indication is the loud "Bang" and a jerk of the steering.
If there was a slow leak going on for say 5 or 10 minutes, the tire "knew" what was happening and it wasn't a "sudden" failure but slow build to an exciting finish

[mel s]

Me thinks anyone who has ever had a tire blowout knows what a "blowout" is.. and that anyone who has never had a blowout will know what a blowout is when they have one...(regardless of the reason the tire blew out).
Mel
'96 Safari