Blowout Question

[GreenImp]

Originally Posted by Tireman9

Rubber strength degrades with time and heat with HEAT being an over-riding contributor. Do you cover your tires with white covers? This can result is a very significant lowering of tire temperature. Every hour of full sun exposure can be equivalent to two to 3 hours of use running down the highway at top speed.

Quick example: 8 hours a day 7 days a week for two months each summer can be the equivalent of 10,000 miles use as far as rubber degradation is concerned. So if we assume a tire is good for 40,000 miles and you park it as in the above example after 3 years you may have "consumed the equivalent of 30.000 mile tire life, just while parked.

OK, OK, I hear you!! (JK!)

After being on my shopping list for far too long, I just ordered some white tire covers. As I see it, the benefits of these covers are twofold...the obvious heat/UV protection, and installing/removing them will create many excellent opportunities to get up close and personal with each tire (for inspection).

[Blackhat6mike]

IMHO, I believe a tread separation would have exponentially less resistance hitting smooth, strong metal sheet than a "metal grate". My liner is bolted directly to the unit's steel frame with large diameter SS bolts. It is meant to absorb most of the energy from a flopping tread. By no means will it go undamaged, but should provide significantly more protection than the piece of very thin sheet metal it is replacing.
The pictures below are of the stock wheel well liner that was on the unit. Good luck trying to convince me the 1/8" steel replacement wheel well will not provide more protection than the original. IMHO it's just common sense. Maybe 40#, not 500#.

[Tireman9]

If others are considering designing their own protective cage to contain parts of a failing you might consider looking at what the tire industry does in the picture on this page.
Of course maybe tire test labs could save some money by using 12 GA sheet metal and a 2x2 14GA support structure.

[Blackhat6mike]

Originally Posted by Tireman9

If others are considering designing their own protective cage to contain parts of a failing you might consider looking at what the tire industry does in the picture on this page.
Of course maybe tire test labs could save some money by using 12 GA sheet metal and a 2x2 14GA support structure.

Only had to read far enough to see the machine was made in China. Thanks, but I'll take my chances with the "scatter shield" I had built. Guess I'm just funny that way.
My unit was designed by academics and "engineers" with scholarly backgrounds and CAD experience. So how did that work out? I don't need a Rolex to tell me what time it is when a Timex works just as well and in some cases, better. I'll endeavor to persevere with my mod.

[dalford]

Originally Posted by Tireman9

Sorry to rain on your parade but 1/8" plate will not solve your problem. Here is what we use around tire test cells. (grill on left) and this is all welded to 2" sq tubing.

Your tire can deliver about 25,000 Lbs force when it lets go and while you may not puncture the 1/8" plate I doubt that you have a support structure behind the plate that is strong enough.
Adding sufficient protection and support structure will almost certainly increase the probability of overloading one or more tires which as you know actually increases the probability of having a tire failure.

IMO you would be further ahead in preventing the failure in the first place.
This can be accomplished by using a TPMS that will warn of any air loss. 2nd you do a complete inspection once a year or every 2,000 miles.
Ensure you have at least a 15% load capacity margin for the heaviest loaded tire and run the tires at max sidewall inflation all the time.

Question concerning max sidewall pressure. I get up in the morning and it is 75 degrees and my tires read 75psi on my tpms. I know once I get on the road the ambient temp will rise and my tire temp will rise and my tires will get to 80psi+ after a short time. Is that a bad decision to think that is ok? Is 80psi at 75 degrees diffent than 80psi at 90 degrees.. I always wonder and want to be safe..

[41ford]

Maybe one day they will have tires like below for our RVs that will not blow out under any conditions or do they have them now?

[Tireman9]

Originally Posted by dalford

Question concerning max sidewall pressure. I get up in the morning and it is 75 degrees and my tires read 75psi on my tpms. I know once I get on the road the ambient temp will rise and my tire temp will rise and my tires will get to 80psi+ after a short time. Is that a bad decision to think that is ok? Is 80psi at 75 degrees diffent than 80psi at 90 degrees.. I always wonder and want to be safe..

If you read my blog and posts from a few others who actually know about tires you will see that we say that you set the pressure before the tires get warmed up. Tires are designed to tolerate daily temperature changes.

You should never bleed air from a tire that is "Hot". In this case "hot" means having been driven on or in sunlight in previous 2 - 3 hours.

Pressure will increase by 2% for each rise in temperature of 10F. Note the internal tire temperature is usually hotter than the reading from a TPMS.

[Tireman9]

Originally Posted by 41ford

Maybe one day they will have tires like below for our RVs that will not blow out under any conditions or do they have them now?

Not yet. Will need big breakthrough in polymer technology. Tire industry has been working on airless tire for 50+ years.

That tire has very specific load and speed limits. But RV owners too often feel they know better than tire engineers so I wouldn't hold your breath.

[Mainframe]

What is a good low cost tpms to buy? I have it built into my TV and I got a warning 2 times.
It worked out well. Just wondering which system is good for adding on to my FR hybrid.

[Tireman9]

Originally Posted by Mainframe

What is a good low cost tpms to buy? I have it built into my TV and I got a warning 2 times.
It worked out well. Just wondering which system is good for adding on to my FR hybrid.

I have a post on my Blog "Best Tpms" where I identify features and benefits I think are good to be considered.

I especially like:

Lifetime warranty
Early warning as soon as tire starts to loose pressure
No 12v cord from monitor (monitor has rechargable battery)

If TPM company has the manual available for download so you can review I like that too.


Yes my blog has a sponsor but I had no say or input into who are sponsord of the blog I write for. I get no commision, never worked for and do not sell TPMS. I bought my TPMS before I started writing my blog.

I bought my TireTraker TPMS, but you need to review your wants and needs to get the unit that is best for you.

[Witch Doctor]

Originally Posted by Tireman9

If you read my blog and posts from a few others who actually know about tires you will see that we say that you set the pressure before the tires get warmed up. Tires are designed to tolerate daily temperature changes.

You should never bleed air from a tire that is "Hot". In this case "hot" means having been driven on or in sunlight in previous 2 - 3 hours.

Pressure will increase by 2% for each rise in temperature of 10F. Note the internal tire temperature is usually hotter than the reading from a TPMS.

I have the same question as Delford above, I understand what you wrote here, I have also read your blog, but that doesn't answer the question he asked. example: You know you don't have a leak, but one morning the temp outside is 75 degrees and the next day it's 70 degrees your PSI will be lower at 70 by 2 or 3 PSI but once you get rolling it's up to normal sidewall pressure. Thanks for your answer. PS: even being inflated to the sidewall PSI which is 65 lbs. which is "D" rated 2 or 3 PSI still gives the tire of 30% over the axle weight that the unit came with, that is what puzzles me. everytime you post and leave a link I read it also, Thanks for being on this web site, very informative....

[Eskimo57]

We had a blowout on Monday (4th of July). Tire pressure was checked before we left, tires have less than 5000 miles on them, it was hot out, 97 degrees.

[Iwannacamp]

Normally I would never question the knowledge of Tireman... I would THINK any protection against flapping tire hair would help. A 1/8" glass will slow a bullet. I think 1/8" is over kill for shielding unless it was allum maybe. JMO

[Witch Doctor]

Originally Posted by Eskimo57

We had a blowout on Monday (4th of July). Tire pressure was checked before we left, tires have less than 5000 miles on them, it was hot out, 97 degrees.

What was the brand of tires you have on and the rating? Do you have a TPMS on them, damage can happen fast, did you just lose that skirting on the fender or did you get more extensive damage? I had 6000 on my OEM tires Trail Express before I had one also... How did you catch it in time? No matter what that is a real bummer.

[Eskimo57]

No TPMS, tires were Towmax, I'm getting GY Marathons when I get the Rv back from repair. TPMS is on the list.

[Blackhat6mike]

Originally Posted by Eskimo57

No TPMS, tires were Towmax, I'm getting GY Marathons when I get the Rv back from repair. TPMS is on the list.

Four of my five blowouts were Towmax with less than 1,500 miles on them. Just a coincidence I guess. Now have M8008s all around and about 3,200 miles on them. Happy Camper

[Blackhat6mike]

Originally Posted by Iwannacamp

Normally I would never question the knowledge of Tireman... I would THINK any protection against flapping tire hair would help. A 1/8" glass will slow a bullet. I think 1/8" is over kill for shielding unless it was allum maybe. JMO

My local "tire guy" is also a stock car racer. We discussed using aluminum rather than steel but decided alum would be too soft to handle the initial impact of a flopping tread. He used steel in his race car where any like damage could occur like a scatter shield around his clutch and "U joints".
I expect some damage, but feel I need something more than paper thin sheet metal to protect my propane line, electrical harness and two water lines. The sheet metal that took the first blowout was turned to trash. Didn't provide ANY PROTECTION and all were ripped out. The 1/8 steel gives me peace of mind that I WILL have protection if it ever happens again. Then again, my new tires are not made in Shan Dong, China.

[Iwannacamp]

Peace is what we seek. The differences in tire mounting/testing equipment are someone is prolly standing close by. You are not protecting flesh and bone you are trying to stop some of the damage.


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[Tireman9]

With many posts from people that suffered a failure there is a statement along the lines of "I just checked the tires that morning" or "50 miles earlier" or two hours before the failure".
I have no doubt that many did check their tires BUT as I covered in a blog post where I said "Don't check your air pressure". I know that sounds like heracy but there is some logic behind the suggestion.

When people check their tire pressure the gauge or air chuck has to force the valve core open so the gauge can get a reading. Sometimes the core can get cocked or a bit of grit can get into the valve in the core as seen in THIS post.

If they don't have a metal valve cap with an internal "O" ring in good condition and don't snug the cap down it is possible for air to leak out of the valve. This slow leak many times will take an hour or two till the air pressure in the tire is low enough for the tire to suffer a "Run Low Flex Failure" or what many call a "Blowout".

As I pointed out a TPMS eliminates the need to check your pressure each day and will warn the driver of a loss of air.

HOWEVER
In Eskimo's case it appears he suffered a tread separation, not a "blowout". This is caused by the deterioration of the rubber around the steel belts. The fact that he checked the air does not enter into this issue. I have posts on how to inspect trailer tires so you can detect a pending failure before the tire comes apart. It is important to understand the "WHY" of a failure if you want to prevent a re-occurance.

[spock123]

A TPMS is piece of mind.


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