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Old 06-29-2015, 10:31 PM   #127
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My gyms have 16000 mile on them in 2 years, still looking good, with 68 lbs of air, mostly travel on 2 lane roads at 63 mph, no problems....
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Old 06-30-2015, 06:22 AM   #128
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Originally Posted by bladesmith2 View Post
The 4 Goodyear tires went south at speeds between 65 and 70 the only time I exceeded 70 is passing. I do not see how 5MPH is causing these failures. I do drive faster now that I got what might be better tires. I only had one Goodyear tire blow out. All other three were ply separations that I noticed before the tires lost air pressure or ruptured(blew-out). If Goodyear makes tires engineered so close to failure that 5MPH causes the tire to fail they need to rethink a 7% margin of error on their tires. I want a tire I can depend on and not be changing out on a trip or on the side of the road. When I decide road conditions allow driving at the legal speed limit I want to have confidence that my tires are up the job. I check the tire temperature every time I get fuel my tires have never been hot enough to be uncomfortable to hold your hand on. They get hotter setting in the hot summer sun. Almost all of my trips are in the cooler months of the year, so I do not see how tire over heating is a factor in these tire failures.
The Airstream trailer has a lower center of gravity and is more aerodynamic than any other trailer I have ever seen or towed. They tow great at 85MPH provided you have a quality tire up to the job.
Allow me to explain why everyone is focusing on the speed issue.

First, we know that trailer manufacturers don't always do a good job of sizing their tires. Whether it is true in this case is unknown.

Second, speed and load carrying capacity are tied together. More speed = lower load carrying capacity. If the tires were on the marginal side to begin with, even a little extra speed could result in a failure.

Third, tires do not forget. They remember everything that happened to them. So even though the tire may have failed when you were traveling below 65 mph, the times when you did go above 80 are not forgotten and contribute to the failure.

And lastly, if you meant "ply separation" to mean what you posted in the photo, then let me assure you that the photo is of a belt separation. The plies are not separated. The tire likely had a cap ply and that is why it looks the way it does.

Put another way, it appears that all 4 tires failed in the same way - they were just in different parts of the failure sequence when removed.
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Old 06-30-2015, 09:39 AM   #129
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Originally Posted by bladesmith2 View Post
The 4 Goodyear tires went south at speeds between 65 and 70 the only time I exceeded 70 is passing. I do not see how 5MPH is causing these failures. I do drive faster now that I got what might be better tires. I only had one Goodyear tire blow out. All other three were ply separations that I noticed before the tires lost air pressure or ruptured(blew-out). If Goodyear makes tires engineered so close to failure that 5MPH causes the tire to fail they need to rethink a 7% margin of error on their tires. I want a tire I can depend on and not be changing out on a trip or on the side of the road. When I decide road conditions allow driving at the legal speed limit I want to have confidence that my tires are up the job. I check the tire temperature every time I get fuel my tires have never been hot enough to be uncomfortable to hold your hand on. They get hotter setting in the hot summer sun. Almost all of my trips are in the cooler months of the year, so I do not see how tire over heating is a factor in these tire failures.
The Airstream trailer has a lower center of gravity and is more aerodynamic than any other trailer I have ever seen or towed. They tow great at 85MPH provided you have a quality tire up to the job.

So now you have two tire engineers that worked for different companies telling you that your tires failed from belt separation.

What I haven't seen is information on the actual loading on your tires as measured on a scale.

I agree with and support Capriracer's comments on tire damage being cumulative and always getting worse as tires do not repair themselves. Once microscopic cracks are formed from overloading when the rubber is hot due to excess speed they can do nothing but grow and they will grow faster when the tire is at higher temperature.

RE margin on speed rating. Do you support the concept that if an engine has a redline of 5,000 it should run forever at 4,999? How much faster can you go than 5,000 and not do any damage to or shorten the life of the engine?

Load & speed are tire as Capri said. Also the damage done with rough roads is not good for tires. If you insist on running at and above the stated limit of the tires why are you surprised when they fail?

I don't see a mention of your actual measured tire loading or the original size or your original cold inflation or your use of TPMS.

Also I still haven't heard the specific "defect" identified. Was it the wrong rubber compoind used? incorrect cure? How was it possible for the tires to operate fine for 17 months with the defect you claim? How did you happen to get 4 tires from the same batch of "defective" tires while most of the others who got tires from the same batch haven't had similar failure rates?
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Old 06-30-2015, 11:06 AM   #130
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Thanks to the tire professionals for chiming in. You all have confirmed and repeated the things that many of us have stated in our individual posts. ST tires are speed rated. If you exceed the speed rating, your tire's load capacity decreases. Damage can be cumulative resulting in failures later even though at failure time the trailer is rolling within its speed rating. The amount of damage that occurs when exceeding the speed rating is dependent upon the amount of weight a tire is carrying and your cold inflation pressure.

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Old 06-30-2015, 01:24 PM   #131
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Can one of the experts please expand on this from Goodyear about 66-75 MPH?

Does this mean a GYM ST225/75/15 LRD inflated to 75psi can handle 75 MPH?
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Old 07-01-2015, 01:25 AM   #132
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Goodyear Marathon tires

The first tire failed after approximately 5 or 6 months of use during the winter months at around 3,000 miles. Tire pressure was kept consistent at 65psi cold. Driving was 100% on paved roads. Traffic was somewhat congested and 2 lane roads so the speed on this trip ranged from 50 to 65 mph often times less. The trailer sets level around 800 to 850 lbs tongue weight. I did not put much water in the water tank, 10 gallons or so. The trailer is a 2014 28' Classic Limited the trailer is heavy but we travel light 250 to 300 lbs of stuff in the trailer. The only option that added much weight was a second ac unit, roof mounted satellite dish and 50amp upgrade. I do not remember the exact weight on each axle they were within 100lbs from front to back axle. The tires are ST225/75R15 rated at 2540lbs each x 4 = 10,160 lbs total the trailer is around 2,000lbs less than the maximum on the tires. I do not remember the exact weight of the trailer when hooked up but it was less than 8,000lbs I have had it on scales several times. the first failure was under these conditions. On this trip I placed my hand on the tires after driving several hours when I was getting fuel the tires were not even warm. outside temperatures ranged from 80deg F to freezing frost on car. Near the end of the trip before pulling out I checked the tire pressure and noticed a drop in pressure, thinking it was a nail started looking closely at the tire an noticed the tread had a bubble under it no nail. Removed the tire and wheel and headed out to the closest Goodyear store. They were happy to sell me a new made in China Goodyear tire for around $150.00. There is no way speed caused the first tire to fail. The second tire failed under similar conditions in the spring approximately another 2,000 miles and 2 months later. I discovered this tire failure the same way as the first one. Another $150.00 made in China Goodyear tire. I think speed played no part in this failure as well. The tire pressure was monitored each day.
I can add this comment, I am not a tire engineer I worked in the other end of the tire business. In the tire department at Montgomery Wards starting in 1970 when I was in high school and latter college 5 days a week mounting 20 to 40 or more tires every day for six years. Almost 2 years at the truck tire center working school buss fleets over the summer. I have handled more tires, fixed more leaks and have seen lots of screwed up tires along with the story line (it just blew up) I can not tell how often I herd that. I notice tires on the cars around me. Almost every time I am getting fuel I tell some one it looks like you have a low tire, most people just drive off with their low or almost flat tire.
I am sure this is why I found the two first tires that failed. On the later trips these trips were out west and faster speeds than the first two. 65 to 70 sometimes faster when passing. No failures. on our next trip to Florida at lower speeds the third tire actually blew out. Then a couple of weeks later at the end of the trip the fourth of the original tires failed. This is the one I posted pictures of this is the only tire I held on to. Only the original tires have failed none of the replacement Goodyear tires failed. I removed all the Goodyear tires and replaced them with Carlisle load range E tires so far after 4,000 miles they have held up even at higher speeds than the Goodyears failed at. The tire place said they were speed rated at 85mph but I have not seen it in print.
As soon as my Airstream is out of the shop the 16" LT tires go on.
Goodyear tires are going on my hay rake, my tractor top speed is 26mph so it should not over speed or over heat the tires.
Carlisle tires are going on a ranch trailer that has rotten tires, so everything has a new home.
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Old 07-01-2015, 05:22 AM   #133
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"I have had it on scales several times."

"I do not remember the exact weight on each axle they were within 100lbs from front to back axle."

"around 800 to 850 lbs tongue weight."...... 28' Classic, I doubt it.

25' Classic.


"I do not remember the exact weight of the trailer when hooked up but it was less than 8,000lbs"

All that info is on your weight tickets....


FWIW....weighing the trailer does little good if you don't save the numbers.

Bob
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Old 07-01-2015, 05:59 AM   #134
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Can one of the experts please expand on this from Goodyear about 66-75 MPH?

Does this mean a GYM ST225/75/15 LR D inflated to 75psi can handle 75 MPH?
Yes, that is exactly what it means - provided you stay within the load limitations.
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Old 07-01-2015, 07:02 AM   #135
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Yes, that is exactly what it means - provided you stay within the load limitations.
Capri, It is quite interesting that GY could be recommending an inflation pressure greater than the max stamped on the tires sidewall! The bulletin says,

"If Goodyear tires, with the ST designation, are used at speeds between 66 and 75 mph (106 km/h and 120 km/h), we recommend the cold inflation pressure be increased by 10 psi (70 kPa) above the recommended pressure based on the trailer placard for normal inflation and load conditions."

Would be interesting to contact Goodyear and speak to a SME if you could actually get to one. I have personally never had any luck in getting to speak to a subject matter expert via a customer service line. They keep them away from the public!

Capri, you are the expert here but for me this bulletin is not clear that you can go above the max stamped on the tire. It is referring to trailer placard requirements. So for the circumstance when trailer placard requirements = max inflation pressure on the tire it is left to the imagination. Of course the load charts show nothing above 65 psi and the bulletin is clear that there is no increase in load with the change in inflation pressure.
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Old 07-01-2015, 07:16 AM   #136
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I've always run our GYM's at 68psi with 1900lbs on each tire @ 60-65mph without any failures.

I believe the 70psi is to help dissipate heat, not to increase load capability.

Bob
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Old 07-01-2015, 08:13 AM   #137
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Bladesmith2,
I think you are making a smart move by going to the 16 inch tires based on the weight of your trailer, distance and highway speeds traveled.
I have traveled out through the Dakota's several times and it seems like all the goose neck trailers hauling cattle and horses are moving right along the highway at 80+ mph. It is rare to ever see an ST tire on these trailers that haul heavy weight by folks working for a living they use LT tires - they just don't have time for bad tires and the livestock being hauled is worth $$ to them.
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Old 07-01-2015, 08:35 AM   #138
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Capri, It is quite interesting that GY could be recommending an inflation pressure greater than the max stamped on the tires sidewall! The bulletin says,

"If Goodyear tires, with the ST designation, are used at speeds between 66 and 75 mph (106 km/h and 120 km/h), we recommend the cold inflation pressure be increased by 10 psi (70 kPa) above the recommended pressure based on the trailer placard for normal inflation and load conditions."

Would be interesting to contact Goodyear and speak to a SME if you could actually get to one. I have personally never had any luck in getting to speak to a subject matter expert via a customer service line. They keep them away from the public!

Capri, you are the expert here but for me this bulletin is not clear that you can go above the max stamped on the tire. It is referring to trailer placard requirements. So for the circumstance when trailer placard requirements = max inflation pressure on the tire it is left to the imagination. Of course the load charts show nothing above 65 psi and the bulletin is clear that there is no increase in load with the change in inflation pressure.
Capri, you are spot on - confirmed by Goodyear. Sorry for any confusion I created.

I sent Goodyear an email this morning via their website and within an hour I had a call from an engineer. He quickly confirmed your interpretation of the Service Bulletin.

I must admit that I was surprised by the level of their customer service and quick response. Kudos to them for their response.
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Old 07-01-2015, 09:41 AM   #139
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Can one of the experts please expand on this from Goodyear about 66-75 MPH?

Does this mean a GYM ST225/75/15 LRD inflated to 75psi can handle 75 MPH?

As Capri said "Yes" BUT this only applies to Goodyear ST Marathon tires and cannot be applied to other types, designs or brand tires any more than a GM bulletin on the optional oil filter to use on their 6L V8 is OK to use on the Ford V10.

Is it allowable yes. Do I think it a good practice No.
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Old 07-01-2015, 09:51 AM   #140
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I've always run our GYM's at 68psi with 1900lbs on each tire @ 60-65mph without any failures.

I believe the 70psi is to help dissipate heat, not to increase load capability.

Bob

Not quite. The increase in inflation is to decrease heat generation. If you don't generate as much heat you don't have to dissipate as much heat.

Heat energy dissipation is based on transfer coefficients of the rubber and metal wheel.
Heat is generated in the belt area (hottest) due to bending of the belt package and rubber. More bending (increased load or lower inflation) will generate more heat. Also faster bending (higher speed) generates heat.

Increased temperature results in a tire "aging" faster ie loosing its ability to resist cracking due to bending. In my June 16 2011 blog post I covered this topic of heat and rubber aging in depth.

Remember rubber is a good insulator so a tire does a poor job of dissipating heat
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