Another tire debate

[Dan and Liz]

Noted previously: Firestone Destination LE2 is an all-season LT tire with same load rating as the Michelins, and slightly better reviews on Tire Rack web site. I put 4 of these on in the spring, have towed about 4,000 miles this year with no complaints, no air loss. So far these seem to be a great solution for us, and at slightly less cost than Michelin. I have no desire to buy in ST tires after reading forums.

[ROBERTSUNRUS]

Hi, question for the tire engineers. I know you have gone over this de-rated thing several times, but in my mind, if a tire has a load rating of 2540 lbs it should be able to handle this load whether it is on a wheel barrow or a Kenworth. Otherwise these numbers are worthless.

[nickmeloy]

Originally Posted by CapriRacer

...

So summarizing:

ST225/75R15 Load Range D = 2540# at 65 psi.

ST225/75R15 Load Range E = 2830# at 65 psi.

LT225/75R16 Load Range E = Calculated at ~ 3360# at 80 psi (3000# rated)

...

May one infer from this information that an ST225/75R15 Load Range E tire run at 65 psig (or perhaps slightly higher psig) is a viable alternative to achieve almost the same level of load capacity as one gets from going the 16 inch LT route?

It is unclear to me whether or not such a change would also translate to fewer catastrophic tire failures such as the ones discussed on this forum.

[jcanavera]

Originally Posted by nickmeloy

May one infer from this information that an ST225/75R15 Load Range E tire run at 65 psig (or perhaps slightly higher psig) is a viable alternative to achieve almost the same level of load capacity as one gets from going the 16 inch LT route?

It is unclear to me whether or not such a change would also translate to fewer catastrophic tire failures such as the ones discussed on this forum.

I'm not sure if that might be a typo. I have not seen an ST tire in that size that has that load rating at 65 psi. Here is the tire spec table and recommended inflation pressure from Maxxis for their ST tires. I used the E rated (10 ply equivalent) prior to getting my Michelin's. This was a step up from the D rated Marathons which came with the trailer at build time.

M8008 ST Radial

The site notes 80 PSI in order to carry 2830 lbs. Speed rating for these are 65 mph. I can tell you that I got to the first trip of year 4 of ownership when I had two tires fail due to the belts starting to separate from the tread.
My inflation pressure was 80 psi. My failure with the Marathons were at the last trip of the third season. So the failure of the Maxxis ST came 7 months later in their duty cycle than the failure of the Marathons.

Personally while you do have the load capacity, the question is will you get 5 years of life from that tire? On a heavier Airstream, it seems like 3 years might be all you can expect from an ST tire before the belt issues start to show.

Jack

[CapriRacer]

Originally Posted by ROBERTSUNRUS

Hi, question for the tire engineers. I know you have gone over this de-rated thing several times, but in my mind, if a tire has a load rating of 2540 lbs it should be able to handle this load whether it is on a wheel barrow or a Kenworth. Otherwise these numbers are worthless.

Here, let me put it like this:

If I have a tire mounted on a mobile crane, there is a difference between the load carrying capacity of that tire when it is standing still (called "stationary") and when it is moving. At "creep" speed (less than 1 1/2 mph), the difference is 30% at the same inflation pressure.

This is important for (and used by) mobile crane operators to determine if their equipment has enough capacity to lift the load needed. If you've ever watched those TV programs where they haul those huge loads on equipment with all those tires, you can be sure the engineers on the project looked very carefully at the speed as a factor in their load carrying calculations.

So it DOES make a difference what equipment a tire is mounted on. Speed, road surface, tire size, and inflation pressure, all play a role in the load carrying capacity. Where the difficulty lies is defining those characteristics.

So if a wheel barrow were used exactly like a Kenworth (or vice versa), then we wouldn't have to delineate the differences in tires - but they are different. In order to help make this easier to deal with, tire manufacturers delineate the type of tire designed for that service by the letters in front of (or sometimes behind) the tire size. Those letters define the usage of the tire.

It is unfortunate that trailer tires are not on par with passenger car and LT tires - and as a result there is much discussion about using P type and LT type tire on trailers. This load carrying capacity thing is confusing if you don't think of the usage as the defining characteristics, rather than the tire itself.

[switz]

Within the last 20 posts or so has been the logic that ST tires are the cheapest tire the factories can buy in volume and they will get the trailer off the factory lot to the dealer's lot. With any luck, the ST tires might last the usual one year warranty of the SOBs or the two year warranty of the Airstream.

My walk through at the very large Airstream dealer where I purchased out first ever RV trailer was amazingly ambivalent about tire maintenance or how to detect issues. The service manager literally has 30+ years working with Airstream products and has seen the tire issues reported here for along time and yet did not train the briefing personnel on informing customers about proper tire care.

After all, the dealers look at a GYM tire failure and it's resulting damage to the trailer as an additional source of service income. That might even be a separate line item on their income statement.

I have used Michelin tires on all of my vehicles for over 47 years and if a newly acquired vehicle came with non-Michelin tires, the Michelins were installed as soon as possible after I took delivery. I have never experienced a Michelin structural tire failure. I have had a few flats due to nails and or screws, but that is not a tire structure issue.

Based upon my experience with Michelin tires and the too many to count tire threads and their tremendous length, I decided to install the Michelin LTX (P) 235/75R15 XL tires as soon as I got the trailer home. I have no regrets in that decision.

I think Airstream has put their toe in the water to test an upmarket higher quality tire on the Eddie Bauer model. After all, with that rear hatch, that model is like a limited capacity semi trailer. They also have the 16" SenDel T03-66655T wheels and Michelin LT 225/75R16E tires in the entrance hallway to the Airstream store at the factory offering to install them onto customer trailers at their service center.

Thus, all extraneous commentary not withstanding, the factory explicitly approves this specific wheel and tire to be installed on Airstream trailers. When I install the same model wheels (color variation of black highlights or plain is not a wheel structural issue) and same model tires and run at their recommended pressure, then my warranty is NOT compromised if there are any structural issues in the trailer during the two years after the sale date. They are on order.

The added bonus of the 16" tire and wheel combination is a slightly higher weight rating of 140 pounds per tire (more load margin for heavier trailer) with no 65 mph speed limitation, they raise the trailer about 1/2" for better ground clearance, they have a larger tire print on the road for better braking, they do not loose air, and have a stellar service history to date.

[Tireman9]

Originally Posted by jcanavera

I'm not sure if that might be a typo. I have not seen an ST tire in that size that has that load rating at 65 psi. Here is the tire spec table and recommended inflation pressure from Maxxis for their ST tires. I used the E rated (10 ply equivalent) prior to getting my Michelin's. This was a step up from the D rated Marathons which came with the trailer at build time.

M8008 ST Radial

The site notes 80 PSI in order to carry 2830 lbs. Speed rating for these are 65 mph. I can tell you that I got to the first trip of year 4 of ownership when I had two tires fail due to the belts starting to separate from the tread.
My inflation pressure was 80 psi. My failure with the Marathons were at the last trip of the third season. So the failure of the Maxxis ST came 7 months later in their duty cycle than the failure of the Marathons.

Personally while you do have the load capacity, the question is will you get 5 years of life from that tire? On a heavier Airstream, it seems like 3 years might be all you can expect from an ST tire before the belt issues start to show.

Jack

Jack, If I read your post correctly it sounds like you have a very high tire failure rate. I am very curious what your actual tire loads are and if they have changed more than say 50# over the past 4 years.

Also when you check your air pressure, do you ever see pressure down by 5 psi or more?

[jcanavera]

Originally Posted by switz

The service manager literally has 30+ years working with Airstream products and has seen the tire issues reported here for along time and yet did not train the briefing personnel on informing customers about proper tire care.

After all, the dealers look at a GYM tire failure and it's resulting damage to the trailer as an additional source of service income. That might even be a separate line item on their income statement.

I have used Michelin tires on all of my vehicles for over 47 years and if a newly acquired vehicle came with non-Michelin tires, the Michelins were installed as soon as possible after I took delivery. I have never experienced a Michelin structural tire failure. I have had a few flats due to nails and or screws, but that is not a tire structure issue.

Based upon my experience with Michelin tires and the too many to count tire threads and their tremendous length, I decided to install the Michelin LTX (P) 235/75R15 XL tires as soon as I got the trailer home. I have no regrets in that decision.

I think Airstream has put their toe in the water to test an upmarket higher quality tire on the Eddie Bauer model. After all, with that rear hatch, that model is like a limited capacity semi trailer. They also have the 16" SenDel T03-66655T wheels and Michelin LT 225/75R16E tires in the entrance hallway to the Airstream store at the factory offering to install them onto customer trailers at their service center.

Thus, all extraneous commentary not withstanding, the factory explicitly approves this specific wheel and tire to be installed on Airstream trailers. When I install the same model wheels (color variation of black highlights or plain is not a wheel structural issue) and same model tires and run at their recommended pressure, then my warranty is NOT compromised if there are any structural issues in the trailer during the two years after the sale date. They are on order.

.

I've owned a travel trailer since 1982. Three different brands and 3 different trailers. With all the tours and training they gave me, no one ever talked to me about tires. I might note that my trailer and towing knowledge came from reading Trailer Life. Not the publication it is today, but back when some of the monthly contributors talked about towing technique, safety, systems and tires. In '82 my trailer came equipped with bias belted tires. I changed them every 5 years and the last set were auto radials. I drove as I drive today 60-65 mph. I always kept them inflated to max sidewall recommendations, and I was careful to purchase the tires to carry the load originally carried by the OEM's that came with the trailer. 14 years I towed that trailer and never lost a tire on the road.

Every trailer since has had ST tires as the OEM. Those first two with ST's were only kept 2 years. So whether I would have seen problems is a matter of conjecture. Interestingly enough those two trailers had the same size Marathon's as what came on my Classic. The big difference were those two trailers never carried more than 2/3rds of the gross of my Classic.

My dealer and a JC Airstream rep at the local Rv show both confirmed that ST's have been problematic on heavier trailers and moving to 16" LT's were a good move on my part. I really believe it will be just a matter of time that Airstream will make the jump. My guess it will next come on the 30' units.

Jack

[ROBERTSUNRUS]

Originally Posted by jcanavera

My dealer and a JC Airstream rep at the local Rv show both confirmed that ST's have been problematic on heavier trailers and moving to 16" LT's were a good move on my part. I really believe it will be just a matter of time that Airstream will make the jump. My guess it will next come on the 30' units.

Jack

HI, I just paid a visit to the brand new Airstream of Orange County and every trailer there [one 2013 and the rest 2014's] all had Goodyear Marathons on them. No Eddie Bauers in stock.

[jcanavera]

Originally Posted by Tireman9

Jack, If I read your post correctly it sounds like you have a very high tire failure rate. I am very curious what your actual tire loads are and if they have changed more than say 50# over the past 4 years.

Also when you check your air pressure, do you ever see pressure down by 5 psi or more?

The last trailer I weighed was my 27', 2001 Safari. Based on Airstreams specs, it was 5,500 lbs dry. I loaded it up with food, clothing and our camping gear. The dealer who had a program to weigh trailers had 4 individual wheel scales. I came in at 6,000 lbs not connected to the tow vehicle with dry holding tanks. I've considered that 500 lbs to be my normal camping load.

My Classic is rated to be able to carry 555 lbs (this is for cargo only). Full holding tanks and propane are considered when coming up with the 555 figure. So for one trip a year (214 miles), I'm calculating I'm at about 9,100 lbs which is the design gross for my trailer. Typically I tow with no more than 2-3 gallons of fresh water. My fresh water tank is 60 gallons. So for the majority of travel we are most likely at 8,500-8,600 lbs.

With the ST tires I'd lose 1-3 lbs per month. Over the winter I'd loose about 10 lbs from winterizing to de winterizing which was on average 4 months.

So far the Michilen's seem to be more stable. I lost 4 lbs over winter. I aired them up to 80 psi. Last check before I left for Moraine View I found them at 82 psi which I attributed to the warmer clime outside in my driveway vs the cool indoor garage where I did the initial fill this spring.

Jack

[jcanavera]

Originally Posted by ROBERTSUNRUS

HI, I just paid a visit to the brand new Airstream of Orange County and every trailer there [one 2013 and the rest 2014's] all had Goodyear Marathons on them. No Eddie Bauers in stock.

Yep they haven't made that jump yet. They definitely are watching this forum to see how the user community's experience plays out. The also are watching the sales at JC on the wheel tire conversions. Corporate change come slowly.

Jack

[Jim J]

Just got back for a Tire Seminar at Camping World today and took away the following advice.

- LT tires can squirm so much the bead loses contact with the wheel when backing up because the sidewall construction is different than the ST.

- Tread belt separation is common when trailer has not been moved for six months and is then taken out - reason given was high sustained static load on single spot of tire. Ther was no way he knew of to visually confirm this. Many people at the seminar had experienced this exact problem and said a second tire blew within an hour or two of the first blowout, and the blowouts caused extensive damage.
- Presenter recommended one or more of the following to prevent this:
- Overinflate tire by 20-25 % when parking for long periods
- Move trailer every 30 days so tires not sitting on the same spot
- Unload the trailer tires by taking weight out of trailer and/or jacking up trailer

- Presenter recommend underinflating tires by 10% from max rated load when traveling to prevent heat build up, he had a table for GYM's that showed the max rated speed vs inflation pressure. Nominally 60 PSI = 60 MPH, 65 PSI = 65 MPH

- Presenter stated driving at higher speeds tends to reduce tire wear and fuel mileage

- Presenter stated that life of a tire was nominally 5 years whether sitting on shelf or rolling along the highway.

Presenter data was from major tire manufacturers including Goodyear.


Jim

[CapriRacer]

Originally Posted by Jim J

Just got back for a Tire Seminar at Camping World today and took away the following advice.

- LT tires can squirm so much the bead loses contact with the wheel when backing up because the sidewall construction is different than the ST.

- Tread belt separation is common when trailer has not been moved for six months and is then taken out - reason given was high sustained static load on single spot of tire. Ther was no way he knew of to visually confirm this. Many people at the seminar had experienced this exact problem and said a second tire blew within an hour or two of the first blowout, and the blowouts caused extensive damage.
- Presenter recommended one or more of the following to prevent this:
- Overinflate tire by 20-25 % when parking for long periods
- Move trailer every 30 days so tires not sitting on the same spot
- Unload the trailer tires by taking weight out of trailer and/or jacking up trailer

- Presenter recommend underinflating tires by 10% from max rated load when traveling to prevent heat build up, he had a table for GYM's that showed the max rated speed vs inflation pressure. Nominally 60 PSI = 60 MPH, 65 PSI = 65 MPH

- Presenter stated driving at higher speeds tends to reduce tire wear and fuel mileage

- Presenter stated that life of a tire was nominally 5 years whether sitting on shelf or rolling along the highway.

Presenter data was from major tire manufacturers including Goodyear.


Jim

Jim,

Thanks for the summary, but there are things about what was said that bother me.

So where and when was the seminar and who conducted it?

Here was what bothers me.

a) I don't think LT tires are built much differently than ST tires - and in particular in the sidewall area. Yes, P type tires are different than ST tires - and I think that is where this is coming from. Yes, I have seen a tire manufacturer make the ST/ LT difference claim, (I think it was Carlisle), but I note with great interest that Carlisle doesn't make LT tires - so how would they know?

- Followup - it was Carlisle.

b) While I tend to agree that not moving a trailer for many months causes issues with the tires, I think it has to do with the flexing helping move the Anti-oxidants (AO's) within the rubber matrix, and not because of the sustained load - and I certainly don't think the tires are failing in the area where ground contact was made. My understand is that AO's slow down the attack by oxygen on the rubber - and its durability - and that results in weather cracking which can be an indicator of the state of the rubber properties. But I also agree it would be difficult to confirm if the contact patch are was involved or not.

Needless to say, I don't agree with the 3 "To Do's". I don't think they do anything effective to reducing the rate of tire failure (with the proviso that "moving the trailer" means something other than 10's of miles of movement.)

c) I really question that presenters information about UNDER inflating by 10% to prevent heat build up. It is just the opposite - and this can be demonstrated easily.

I am going to stop there because item "c" is proof to me the presenter doesn't know what he is talking about.

So, please, please, please,: When, Where, and Who.

[jcanavera]

I attended a tire safety seminar held by Seminars | RV Safety.com. Never did we hear any advice to UNDER inflate our tires. Their advice was to run them at the stated max cold sidewall pressures. They also talk about UV exposure and that one of the best things was running the tire to flex it and help keep the AO's distributed within the tire.

Their biggest advice was to weigh your trailer and look at the load on each wheel to make sure you aren't overloading, watch the inflation, and speed. Their stance was that by exceeding the speed rating of a tire, you build up heat faster than the tire's ability to shed it, which eventually leads to failure.

Here a link to RvSafety's locales this year where you can an each wheel weighing.

http://rvsafety.com/weighing-schedule/

[Jim J]

H Capri, Appreciate your input, forums are the place to discuss different ideas so you may not agree with what I reported from the seminar delivered by a camping world technician at the New Braunfels, TX location on Saturday August 10.

Here a couple of links to information form Good Year on tire inflation. The inflation pressure marked on the sidewall is for max rated load at 65 MPH. You may go lower or higher to accommodate lower loads or higher speeds.

http://www.tirerack.com/images/tires...plications.pdf
http://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

[GCinSC2]

Just saying hello and saying this stuff is interesting reading about tires. Nothing to add or debate, just watching with significant interest.

Gary

PS I did take a pic of those Michelins at Jackson Center this summer in the lobby, yup.

I just took my rig out yesterday for a 1 hour spin just to run it and check prior to our next trip. I have recently started storing with a pair of strong screw jacks from 1 ton Dodge's taking a good amount of weight off of the tires and axles. Not in the air, but jacks are taking a good amount of weight.

[Alphonse]

Originally Posted by jcanavera

Correct my original failure was the ST D rated 225 75R 15 Marathon, inflation 65 psi. The two tires that failed next were ST E rated 225 75R 15 Maxxis inflation 80 psi.

Currently I using the LT E ratedMichelin 225 75R 16 inflation 80 psi. No failures as of now but I just am on one year of use. The Goodyear failed on my last tow of its 3rd season. The 2 Maxxis tires failed on their first tow of season 4.

Jack

Jack,
Were the failures on the front or rear axles or both?
Thanks

[jcanavera]

Originally Posted by Alphonse

Jack,
Were the failures on the front or rear axles or both?
Thanks

Front axle. You would think that would be a smoking gun, but at this point I'm not sure what the correlation might be. No abnormal tread wear and the trailer sits level when towing.

Jack

[Tireman9]

Originally Posted by Jim J

Just got back for a Tire Seminar at Camping World today and took away the following advice.

- LT tires can squirm so much the bead loses contact with the wheel when backing up because the sidewall construction is different than the ST.

- Tread belt separation is common when trailer has not been moved for six months and is then taken out - reason given was high sustained static load on single spot of tire. Ther was no way he knew of to visually confirm this. Many people at the seminar had experienced this exact problem and said a second tire blew within an hour or two of the first blowout, and the blowouts caused extensive damage.
- Presenter recommended one or more of the following to prevent this:
- Overinflate tire by 20-25 % when parking for long periods
- Move trailer every 30 days so tires not sitting on the same spot
- Unload the trailer tires by taking weight out of trailer and/or jacking up trailer

- Presenter recommend underinflating tires by 10% from max rated load when traveling to prevent heat build up, he had a table for GYM's that showed the max rated speed vs inflation pressure. Nominally 60 PSI = 60 MPH, 65 PSI = 65 MPH

- Presenter stated driving at higher speeds tends to reduce tire wear and fuel mileage

- Presenter stated that life of a tire was nominally 5 years whether sitting on shelf or rolling along the highway.

Presenter data was from major tire manufacturers including Goodyear.


Jim

And the "presenter" had a Bachelor of Science degree from what school? and had worked as a Tire Engineer with product responsibility for what tire company?

I would challenge the "presenter" to provide any scientific date that supports his recommendation to "underinflate" a tire.

I do have a BSME from Ohio Northern Univ. I do hold two US Patents for tire designs. I do have 40 years experience with tire design responsibility. I have been personally responsible for conducting well over 10,000 tire autopsies to learn the "cause" for the failure.
While he said some correct things he clearly has had no formal training in tire design and I would doubt he has ever performed a failed tire autopsy.
I have given training class to US DOT engineers on failed tire inspection and analysis.

I wonder if the "presenter" can explain this failure.


SO here we have a "new" tire i.e. zero miles, mounted as a spare. Clearly it has failed. How does the idea of parking for long time causing failure work? Capri, you are not allowed to answer.


I think the presenter should have informed the people "Hi, I'm not a real tire engineer, but I play one at Camping World"

[Jim J]

Tireman, Glad you commented. What did the presenter say that you agree with? And a question for you: What is the tire construction difference between an ST tire and LT tire? Do you have a preference for use on Airstream Trailers?

Jim