Weird Marathon Picture - what happened?

[xrvr]

I understand, when the setup is right it's hard to not overdo it. Have a great trip, Florida is nice this time of year if you can swing this way. Top of ga AS park is open all year if you get near north ga. Have fun, enjoy the holidays.

[Tireman9]

Originally Posted by Andrew T

We returned from our trip to California from London last week. As I mentioned in an earlier post this was the first longer trip I had taken on Marathon's in a long time. Likely the first one since the change to Dexter axles.

I noticed that things move around much more in the Airstream than they do with the 15" Michelins I normally run. However I made it without a single tire problem. This was a 28' International so a fairly light trailer.

I ran them at 45PSI which is 5 PSI above the recommended pressure for the load they were carrying. Average speed was 70 MPH however the hottest days were in the Mid 70's. Tires were never warm. I did not hit any curbs but did do plenty of tight turns.

I thought maybe one might have a shifted belt explaining all the movement in the unit so we pulled them off yesterday and checked the balance and all 4 were fine. Maybe Marathons are getting better but I would still put Michelins on next time.

And check the weather before you head off across Highway 60 from Phoenix to Interstate 25. Turns out it goes to 8000 ft and there was a good snow storm up there. Wound up spending the night in Spencerville AZ. Not the end of the earth but you can see it from there.

Andrew T

"Average" of 70 means some significant time above 70. So now that you have done irreparable damage to the belt structure will you remember that you made the decision to ignore the Max speed rating of your tires if you ever have belt area problems with the tires?

[m.hony]

Those tires will fall apart anyway. I averaged 60 mph towing and had tread separation on Good Year Marathons within 3 years.


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[Ampman]

Sometimes you have to go above 65 mph to get away from traffic clusters or pass others. It happens. There should be enough confidence in your tires to be able to do that. But with the current ST's I guess they don't build in the extra margin of durability for that. Shame on those tire manufacturer's for poor quality products.

[Andrew T]

"Average" of 70 means some significant time above 70. So now that you have done irreparable damage to the belt structure will you remember that you made the decision to ignore the Max speed rating of your tires if you ever have belt area problems with the tires?


From Albuquerque to Dayton we had a bit of a tail wind or no head wind so I had the cruise set at 75 for that stretch. Not that I recommend doing so, I have an extremely stable combination, the traffic was lite and I have 40 years and a few hundred thousand miles of towing experience. Even with that I should not have been towing that fast.

In theory the higher speeds are supposed to damage the tire due to heat build up which should not be an issue this time of year. However I have seen lots of damaged Marathons that never saw high speeds or high temperatures. For example plenty of square trailers are to hard to pull to get to high speeds. So that was why I was pleasantly surprised to see that this set has not gone out of balance during this trip.

So we either got lucky with this set or maybe they have improved their process and they are getting better? The first Marathons from the early 90's had far fewer defects so it may be more of a manufacturing issue than purely a design one.

Still don't care for the ride however and I would still recommend Michelins, 112 MPH speed rating on those.

Merry Christmas!

Andrew T

[switz]

Comparing the incremental cost between the 15" GoodYear ST225/75R15D tire and the 15" Michelin LTX (P) 235/75R15 XL tire to the typical insurance deductible when there is a tire failure that tears the side out of the Airstream makes a convincing argument to consider the Michelin tires.

I have had GYM tire failures on my tandem motorcycle trailer and sure would not want that experience with an Airstream. Thus, we have Michelin tires on all vehicles including the Airstreams. Great piece of mind for me.

[Tireman9]

Originally Posted by m.hony

Those tires will fall apart anyway. I averaged 60 mph towing and had tread separation on Good Year Marathons within 3 years.


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High speed, in itself is not the major problem. Heat either from long exposure to direct sunlight or extended high speed that generates excess heat, coupled with the Interply Shear force on the belts due to high loading ( less than 15% margin on max load0

And did GY cover you under their warranty?
And did you file a complaint with NHTSA? No complaints means no investigation. which means no possible recall and no improvement in tire quality.


As the saying goes "We have met then enemy and it is us?



But the condition as seen in the OP post #1 is not a belt separation or a "blowout"

[Tireman9]

Originally Posted by Ampman

Sometimes you have to go above 65 mph to get away from traffic clusters or pass others. It happens. There should be enough confidence in your tires to be able to do that. But with the current ST's I guess they don't build in the extra margin of durability for that. Shame on those tire manufacturer's for poor quality products.

ST type tires are designed to meet regulations established when 55 was the max legal highway speed. RV companies know this yet they resist selecting tires with higher speed capability. It is not the tire mfg responsibility to select tires to be placed on a vehicle. It is well established that that decision is 100% the responsibility of the RV company.
It could be argued that it is the RV companies that are the ones doing the "mis-application"
Owners want low cost but are refusing to accept the trade-off in max speed capability to get the low cost they demand.

[Tireman9]

Originally Posted by switz

Comparing the incremental cost between the 15" GoodYear ST225/75R15D tire and the 15" Michelin LTX (P) 235/75R15 XL tire to the typical insurance deductible when there is a tire failure that tears the side out of the Airstream makes a convincing argument to consider the Michelin tires.

I have had GYM tire failures on my tandem motorcycle trailer and sure would not want that experience with an Airstream. Thus, we have Michelin tires on all vehicles including the Airstreams. Great piece of mind for me.

How are you considering a tire with 2,540# capability equivalent with a tire that would be rated to carry 1,918# max?

If the GAWR is even 1# above 3,837# Federal Regulations do not allow the identified GY tire to be used by the RV company.

[m.hony]

Originally Posted by Tireman9

High speed, in itself is not the major problem. Heat either from long exposure to direct sunlight or extended high speed that generates excess heat, coupled with the Interply Shear force on the belts due to high loading ( less than 15% margin on max load0

And did GY cover you under their warranty?
And did you file a complaint with NHTSA? No complaints means no investigation. which means no possible recall and no improvement in tire quality.


As the saying goes "We have met then enemy and it is us?



But the condition as seen in the OP post #1 is not a belt separation or a "blowout"

No. I did not file a claim. I don't want their crumby tires.
No. I did not file a claim. What's the point? I got 2 years, 10 months, and possibly 30,000 miles out of them. No ST tire will do much more than that.
I made a conscious decision (for the better I think) to get 16" wheels and LT tires- no speed limit worries- no load limit worries- will last 5 years or more-
No worries!
I still tow at 65 mph max for fuel economy and safety margin- increased following distance and decreased stopping distance-
I did what I wanted to- what I thought was the right thing and the best thing-
Already had a bad taste in my mouth for Good Year tires dating back to the 80's and Viva tires that did not last as long as the should have and had a weird tread wear pattern although they were properly inflated, rotated, balanced- I did the best I could and the tires were still bad- I did my part- I did my due diligence-
Why am I defending myself?
I'm grown-
I pay my own bills-
Freedom!


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[Bill M.]

"How are you considering a tire with 2,540# capability equivalent with a tire that would be rated to carry 1,918# max?"

They are not "equivalent" and the tires have to have a higher rating than the max axle rating. We understand that.

But I also think that while one says 2540 and the other must be used at 1983 or less it is not a direct comparison because the ratings are arrived at by different tests. I know that with my 3200 lb axle rating I would rather have the 1983 at 50 pse from the XL tire than the 2540 at 65 from the ST tire. Let me ask, would the XL tire pass the test at a higher rating than 1983 if it was tested exactly like the ST tire? My assumption is that it would. Would the ST tire pass the same test as the XL tire does and be rated at 1983 or higher? I do not think so.

[m.hony]

Not considering them equivalent-
Considering the LT tire superior-


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[switz]

So the 25' to 28' Airstream trailers share two 3,800 pound axle rated axles. The 23' models use two 3,000 pound rated axles. The 16' Bambi has a 3,500 pound rated axle. Theses axle specifications are from the 2016 Bambi, Flying Cloud and International models parts list.

Thus two 15" Michelin LTX (P) 235/75R15 XL sidewall rated 2,183 pounds @ 50 psi and are derated to 1,985 pounds each exceeds the axle ratings for the most popular models of Airstream. The two 23' models that come with 14" GYM ST215/75R14C tires rated 1,870 pounds @ 50 psi can support these 15" Michelins on SenDel T03-56545T wheels. I installed the 15" tire and wheel conversion on our 23D.

The 22' Bambi has a single 4,500 pound rated axle, the 19' models have a single 4,300 pound rated axle, the 20' Flying Cloud has a 5,000 pound rated axle, the 30' Flying Cloud and International models have two 4,500 pound axles and the 31' Classics have two 5,000 pound rated axles. The 16" Michelin LT225/75R16/E LTX M/S2 is rated 2,680 pounds @ 80 psi and thus has the necessary load capacity for these longer twin axle or heavier single axle trailers.

Before decrying the 170 pound cushion of the 15" Michelin tires on a 3,800 pound axle, Airstream put the 15" GYM ST225/75R15D rated 2,540 pounds @ 65 psi tires on the 5,000 pound rated axles of the Classic and the 20' Flying Cloud with only a 80 pound cushion.

The Dodge factory recommended tire pressure for the factory installed 16" Michelin LT265/70R17E tires that are rated 3,195 pounds at 80 psi equals the rear axle rating on my 2012 Dodge am 2500HD Cummins and is 20 pounds over the front axle rating per the Michelin tire pressure vs load capacity table. We run both front and rear tires at 80 psi when towing.

Thus, the user does have a viable choice to use a Michelin tire of the proper size if the the service history of the Goodyear ST tires is worrisome.

[tjdonahoe]

If my 225/75/15 marathon trailer tires are good for 2540 lbs times 4 is equal to a gross of 10160, last time it was weighed fully loaded we were at 8800 lbs and with 20000 miles with 1/2 tread they did good....

[CapriRacer]

Originally Posted by tjdonahoe

If my 225/75/15 marathon trailer tires are good for 2540 lbs times 4 is equal to a gross of 10160, last time it was weighed fully loaded we were at 8800 lbs and with 20000 miles with 1/2 tread they did good....

Just a couple of thoughts:


1) It would be highly unusual if all 4 tires on a travel trailer carried the same load. There is front to rear and side to side variation. The conservative guy in me says the worst case is 115% of the average.


2) ST tires are speed restricted to 65 mph. In order to operate at 85 mph (the value I think should be used by trailer manufacturers), the load table values would need to be reduced by 20%.


3) My experience says that tires should not be operated at more than 85% of their rated load (which includes those 2 things above).


So I think the calculation is much more complex.

[PaulnGina]

The 6 Commodore ST225/75-R15 tires we put on our Avion last Spring are N113's (87 MPH). I'll be watching them, but so far, so good.

Originally Posted by CapriRacer

Just a couple of thoughts:

1) It would be highly unusual if all 4 tires on a travel trailer carried the same load. There is front to rear and side to side variation. The conservative guy in me says the worst case is 115% of the average.


2) ST tires are speed restricted to 65 mph. In order to operate at 85 mph (the value I think should be used by trailer manufacturers), the load table values would need to be reduced by 20%.


3) My experience says that tires should not be operated at more than 85% of their rated load (which includes those 2 things above).


So I think the calculation is much more complex.

[Tireman9]

Originally Posted by PaulnGina

The 6 Commodore ST225/75-R15 tires we put on our Avion last Spring are N113's (87 MPH). I'll be watching them, but so far, so good.

While I feel that tires with a Service Description i.e. Speed Symbol and Load Index are probably a bit more robust than tires without a Service Description, I would still limit the max operating speed to 75 unless you can find something in writing from the tire mfg indicating otherwise. IMO there is a good possibility that some off-shore tire companies that make "container tires" simply ran a tire on the drum test and used the results of that test as the basis for marking the tire. Unlike other specifications and regulations the Speed Symbol was not a regulatory item but just a test established by Society of Automotive Engineers so unless the regs. have been changed there is no requirement for 100% of tires being made to be capable of passing that test.

In the US market the Speed rating is really more of a handling rating and certainly does not mean a tire can run that speed for full tread wear life. For some of the off-shore companies that have little real experience in the US market and with no technical center located in the US, I think they will soon discover that anything above an L (75) may result in higher warranty complaints.

Of course based on the majority of responses I get when I ask if people, that have had tire failures, if they have bothered to file a complaint with NHTSA or file a warranty complaint with the tire company I am not holding my breath till warranty costs increase.
If we, the RV community can't be bothered to make the minimal effort it takes to file such complaints then IMO we are stuck with lower quality tires. Unless and until the bottom line of a tire company or RV company is hurt with warranty costs or the cost of a recall there is no incentive to improve the real quality of the tires on the market.

[tjdonahoe]

I should have added to post 174, I only drive 62-63 mph and mostly 2 lane skinny roads, you don't see much from the interstates, and the trailer and pickup will last longer, I have been in a hurry all my life driving the big trucks, I don't have to do it anymore...

[PaulnGina]

Originally Posted by PaulnGina

The 6 Commodore ST225/75-R15 tires we put on our Avion last Spring are N113's (87 MPH). I'll be watching them, but so far, so good.

I'll also add that I drive very conservatively based on the number of travel trailers/5w's that pass us. We stick to 60 mph, inch up to 65-70 approaching a steep hill.
For me, the N113 rating is hopefully just more insurance.


PaulnGina
1987 Avion 34W
1995 Ford F250 7.3L PowerStroke

Blessed and highly favored

[tjdonahoe]

Another thing I do is rotate and balance the as tires at least once a year, that helps keep everything even...