Blowout on the Continental Divide

[TravlinMan]

I am plannin on switching out to LT tires soon but my Goodyear Endurance have got over 12k miles on em so far and they look pretty great.

I am considering switchin both the truck and trailer tires to Falken Wildpeaks which I ran on my Jeep and loved. They come in LT225/75R16 for the trailer and also LT285/75R17 for the truck. I ran em on the Jeep for years and they ended up bein one of my favorite tires.
http://www.falkentire.com/tires/ligh...dpeak/t3w-tire

[rwsjms7]

What is the difference between ST and LT?

[TravlinMan]

Originally Posted by rwsjms7

What is the difference between ST and LT?

Well slowmover is very passionate about this so he will have a more thorough answer.

ST are special trailer tires. They are apparently made for trailers to help prevent sway with stiffer sidewalls but there are opinions that since they ain't legal to use on a passenger vehicle, they shouldn't be used at all. Slowmover and many others believe that they should not be used ever, with a lotta good reason. However, some folks have argued the opposite to me, that I'm silly switchin to LT (which are light truck/suv tires) on a trailer because I should be usin the tires that were made for trailers. They say they LT on a trailer is unsafe because of sway and pressure.

Then again, many folks say you must use a high end sway control device, which would greatly reduce any chance of sway with LT or ST tires. So then I reckon it comes down to blowouts. I do not know if there is data sayin more blowouts happen with ST than LT but I think there may be.

[DKB_SATX]

Originally Posted by rwsjms7

What is the difference between ST and LT?

ST (Special Trailer) tires are not good enough to be approved for passenger-carrying applications. LT (Light Truck) tires are, with higher speed ratings and a better reputation for being well-made and for being reliable over time.

[SeaLevel]

Originally Posted by rwsjms7

What is the difference between ST and LT?

https://www.tirerack.com/tires/tiret...jsp?techid=219

Keep in mind this was written before the Goodyear Endurance tires were released, and those tires carry a higher "N" (87mph) speed rating. Not that you should ever pull a trailer that fast, but it's good to know they are a better engineered tire than the Marathons.

[Action]

Higher load ratings
Higher speed ratings

Higher class of tire that can handle more stress.

For the tire of any type that is properly inflated and has lots of margin no big deal. Trailer tires have not always had much margin in the history of trailers in general. Historically trailers have not been treated like passenger vehicles by trailer manufacturers. Many passenger vehicles have huge margins on the tires that are installed.

If the tire spec was 100 for trailers, any tire that was 100 or 101 or more was acceptable in the trailer industry. It was the end users responsibility to maintain to the highest degree that same tire. Fully inflated most passenger vehicle tires could carry twice the load as that passenger vehicle tire actually sees. Almost no one ever considers the load capacity or speed rating on a passenger vehicle. Because the margins are so much greater. In the trailer world it was customary to install tires that have zero margin or a margin that is extremely small compared to other vehicles that operate on the roads.

ST tires get a bum rap. Some of that is due to the capacity of the tire used versus the actual load and condition the tire is exposed to in real life. A marginal ST tire is going to under perform against a P or LT designated tire that may have margins that are far greater than the ST tire.

>>>>>>>>>>>>>Action

[Overlanding]

So many great inputs from this group!

Goodyear dealers are clear that the Marathon has been replaced with the Endurance. https://corporate.goodyear.com/en-US...iler_tire.html.

We Airstreamers haul transcontinental distances in tough road and heat conditions. With careful inflation, and keeping load and speed within limits, we need tires that do not come apart.

[Tireman9]

Originally Posted by carl2591

actually you fill tire to carry the capacity of the weight you are towing. Goodyear and Michelin have guides on pressure for weight. On my 31 classic with 16" Michelin tires, they have a max air pressure of 80 psi. the chart states for my weight, some 9K, each tire should be inflated to 68psi not 80 psi.

when you fill tires to max the ride is very rough on trailer and not needed unless the tires are not rated for the weight they carry.

with the GYM it a crappy tire that fails mostly from sidewall failure and or tread separations.

Sorry but inflating to the measured load is correct for Motorhomes but not trailers. Trailer tires should be inflated to the psi molded on the tire sidewall. You will also see that number on the trailer certification label. The belt Interply Shear in trailer application is 20 to 24% higher for trailers. Sorry I can't post the pink so you will need to Google "Interply Shear tires" if you want the details.

Having said that the OP picture has some signs of a Run Low Sidewall Flex failure. Would need better & more pictures of the failed tire to confirm. If you lose air it doesn't matter where the tire is made. It will fail.

[Tireman9]

Originally Posted by SeaLevel

https://www.tirerack.com/tires/tiret...jsp?techid=219

Keep in mind this was written before the Goodyear Endurance tires were released, and those tires carry a higher "N" (87mph) speed rating. Not that you should ever pull a trailer that fast, but it's good to know they are a better engineered tire than the Marathons.

You do realize that the load formula the tables are based on are based on a 65 mph max speed. DOT does not have a new high speed test for ST tires. In fact ST tires are tested to standards from the 70's while Passenger and LT tires have new tests from 2002.

The SAE speed test is only a 30 minute step speed test. pretty easy to pass. Even many used tires can pass the test.

Since it is the air that supports the load I know of no magic rubber that will allow an ST tire on a trailer to support more load than an LT on a pickup which are both driven on same roads and same speeds.

If in fact it was "better engineering" at GY one has to wonder why first line LT tires don't have the same load rating as the ST tires made by GY.

[Bill M.]

"If in fact it was "better engineering" at GY one has to wonder why first line LT tires don't have the same load rating as the ST tires made by GY."

Perhaps because they test them to markedly different standards?

[Tireman9]

Originally Posted by lwinkler

This is a blowout near Durango on the way back from Chimney Rock. No place to pull over. Luckily the blowout was on the curbside. Changed tire on the road in 10 minutes - No damage. Heard the blast and saw the puff of black smoke came to an immediate stop. Our traveling companions thought my engine had blown up. We had walkie talkies and were able to control traffic. Carlisle tires.

FYI
What I see in not a "Blowout" AKA Run Low Flex Failure
but is a Belt/Tread separation.

Two different conditions have two different causes. If we don't know the cause of the problem we may not take the proper corrective action.

Another way to think of this would be to say someone is having of a heart attack when in reality it was stroke which is not the same thing and the corrective steps are not the same.

[KK4YZ]

Originally Posted by Tireman9

FYI
What I see in not a "Blowout" AKA Run Low Flex Failure
but is a Belt/Tread separation.

Two different conditions have two different causes. If we don't know the cause of the problem we may not take the proper corrective action.

Another way to think of this would be to say someone is having of a heart attack when in reality it was stroke which is not the same thing and the corrective steps are not the same.

@tireman, what do you see as the most common causes of belt/tread separation, and how would you avoid it?

[Tireman9]

Originally Posted by KK4YZ

@tireman, what do you see as the most common causes of belt/tread separation, and how would you avoid it?

You should have read my post HERE on Why Tires fail.

I wrote this just for this Airstream forum as I am not allowed to post direct links to my RV tire blog that has some 270, company neutral posts on tires and related components.

Sorry but I simply can not re-post all my blog posts. I started to do that on one forum but that ended up getting me banned from an RV forum for offering too much fact based information that didn't support the forum sponsors products.

[Woosch]

Did you ever make it to Portland?

[zapper]

You were lucky. Good to hear you were/are safe. Also appears as though there was no damage. Lucky twice. Endurance GY tire are a new GY product not much feed back on them yet. Hope they are better than the GYM. Luck gets you by only for so long. Good luck.

[Aprilrivet]

Why on earth do you want to go 75 mph ?

[carl2591]

Tireman so now you have me interested in this pressure thing.

what is main difference between tire pressure on Trailer vs MH when it comes to load weight on tires?? the VIN tag on my unit shows the ST tires at 65 PSI. I run by LT tires at 68 psi according to tire load info at Michelin and the weight of my TT with water in tanks, loaded ready to go camping food and all.etc.

the LT tires show a max of 80 psi which would bang the crap out of every thing in the AS going down the road, especially in SC on I95, such a rough road.

I read post of guy using LT tires going thousands of miles with PSI's at 65 to 70 with no issues they report..

I have read some of your blog post and understand your experience in this field but think that the max psi on trailer tires might need to be reevaluated with all the evidence saying other wise.

thanks for your input on this issue.

Originally Posted by Tireman9

Sorry but inflating to the measured load is correct for Motorhomes but not trailers. Trailer tires should be inflated to the psi molded on the tire sidewall. You will also see that number on the trailer certification label. The belt Interply Shear in trailer application is 20 to 24% higher for trailers. Sorry I can't post the pink so you will need to Google "Interply Shear tires" if you want the details.

Having said that the OP picture has some signs of a Run Low Sidewall Flex failure. Would need better & more pictures of the failed tire to confirm. If you lose air it doesn't matter where the tire is made. It will fail.

[CapriRacer]

Carl,

If you and Roger will allow me to join the conversation:

First, you have to be very careful about nomenclature. I suspect when Roger is talking about inflating trailer tires to the max on the sidewall, he is referring to ST tires, and not LT tires on a trailer.

Ya' see, the way ST tire loads are calculated is different than the way LT tires are calculated. If you do the math, you'll find that an LT tire carries less load for a given pressure than a similarly sized ST tire. So if you are using an LT load table, you are in essence inflating the tire more than a comparable ST tire - and that is what Roger was getting at (I think).

Further, I am of the opinion that the problem with high inflation pressure causing a rough ride in the trailer is a trailer suspension problem. Frankly, travel trailers have pretty crude suspensions systems - ones that do not result in a soft ride. I think the idea of using a lower inflation pressure is just a way to deal with a shortfall of such a crude layout.

A better way to cope with the crude suspension would be to use a much larger tire and inflate it to a lower pressure - but the trailer manufacturers generally don't give you enough room to do that. Take a look at how much room there is under the fenders of a pickup truck that uses LT tires (although some of that is due to the larger diameter tires compared to the base vehicle.)

[Tireman9]

Originally Posted by Aprilrivet

Why on earth do you want to go 75 mph ?

Because they can. At least for a while and they do pay the price with shorter tire life.

[Tireman9]

Originally Posted by CapriRacer

Carl,

If you and Roger will allow me to join the conversation:

First, you have to be very careful about nomenclature. I suspect when Roger is talking about inflating trailer tires to the max on the sidewall, he is referring to ST tires, and not LT tires on a trailer.

Ya' see, the way ST tire loads are calculated is different than the way LT tires are calculated. If you do the math, you'll find that an LT tire carries less load for a given pressure than a similarly sized ST tire. So if you are using an LT load table, you are in essence inflating the tire more than a comparable ST tire - and that is what Roger was getting at (I think).

Further, I am of the opinion that the problem with high inflation pressure causing a rough ride in the trailer is a trailer suspension problem. Frankly, travel trailers have pretty crude suspensions systems - ones that do not result in a soft ride. I think the idea of using a lower inflation pressure is just a way to deal with a shortfall of such a crude layout.

A better way to cope with the crude suspension would be to use a much larger tire and inflate it to a lower pressure - but the trailer manufacturers generally don't give you enough room to do that. Take a look at how much room there is under the fenders of a pickup truck that uses LT tires (although some of that is due to the larger diameter tires compared to the base vehicle.)

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