Michelin Defender LTX M/S 235/75-15 109T XL

[TheCabin]

Tireman9,

Thank you for this feedback.

When they mention the XPS Rib is for RV applications, is that both motorhomes and travel trailers (multi-axle)? I ask this because some people say RV for motorhomes and not trailers.

[Air Cruiser]

TheCabin, I realize you are asking Tireman9, but since our AS is the same length as yours, I thought I'd share this with you. In the Spring, 2011, we upgraded our axles to 3500 lb. axles to accommodate a 16" wheel and purchased Michelin XPS 16" tires and couldn't have been more pleased! We have had no issues whatsoever and have been able to travel down the highways relatively carefree and stress free. We will soon be replacing these tires do to aging out and plan to put the same type tires on again.

Deb

[TheCabin]

Air Cruiser, thank you for your comment. TireRack list the XPS Rib LT225/75R16 at 29.4" diameter which I guess should fit ours too. Since Michelin considers the XPS Rib suitable for RVs (#100), I am more interested except for the 80 psi. Still curious if they will warranty them on trailers.

[Rocinante]

Hi there. Michelin customer service line would likely be happy to answer that one. It will be interesting to see what you learn.

[4Kilefamily]

Just wanted to chime in so it will be easier to get updates on this thread as people start to post their results later this year when the new Michelin Defenders come out for us 15" wheel users. I'm just barely getting by with my GYM ST tires by changing them out every 2 years. 10,000 miles is maximum before the tire tread starts to show signs of separation. Can't wait to hear how good the new Michelins will be for the 15" wheels.

[Tireman9]

Originally Posted by TheCabin

Tireman9,

Thank you for this feedback.

When they mention the XPS Rib is for RV applications, is that both motorhomes and travel trailers (multi-axle)? I ask this because some people say RV for motorhomes and not trailers.

I feel that this thread is a discussion on RV trailers. In my experience trailers appear to start life with a very small load capacity margin while Class-C Rvs for the most part are being delivered with LT tires that have better speed capability and many will have a reasonable load capacity as they come with LR-C tires to start with.
Class-C motorhomes do not have the Interply Shear issue seen on multi axle trailer so even with the same static load I would expect a tire in motorhome application to last longer than an identical tire in multi-axle trailer application.

XPS-Rib is probably reasonable for both applications as ling as actual load is taken into consideration.

[franklyfrank]

Originally Posted by Rocinante

Hi there. Michelin customer service line would likely be happy to answer that one. It will be interesting to see what you learn.

I have 15" Michelins on my 2013 30' International now. They are great tires. No anxiety about keeping to 65 MP and under and even though I check them religiously having acquired the habit with the POS GYM tires I rarely have to add air,and when I do it is no more than 1 or 2 psi.
Michelin LTX MS/2 P235 R/15 T- 108 2,183 lbs at 50 Psi.
At that inflation it give you a nice ride.
The issue of the sidewall torque is over hyped with these tires. You get much more sidewall stress going around a sharp curve with a loaded pick up or banging into a curb.These tires are tough and can take it.

The ST standards were written when tire technologie was not as advanced as it is today and has not been updated. However due to the lawyer class being forever on the prowl for an easy buck the tire manufactures are cautious with what they advertise.

[Tincampers]

Originally Posted by franklyfrank

I have 15" Michelins on my 2013 30' International now. They are great tires. No anxiety about keeping to 65 MP and under and even though I check them religiously having acquired the habit with the POS GYM tires I rarely have to add air,and when I do it is no more than 1 or 2 psi.
Michelin LTX MS/2 P235 R/15 T- 108 2,183 lbs at 50 Psi.
At that inflation it give you a nice ride.
The issue of the sidewall torque is over hyped with these tires. You get much more sidewall stress going around a sharp curve with a loaded pick up or banging into a curb.These tires are tough and can take it.

The ST standards were written when tire technologie was not as advanced as it is today and has not been updated. However due to the lawyer class being forever on the prowl for an easy buck the tire manufactures are cautious with what they advertise.

Did you take the trailer to the tire dealer to get them mounted or did you just take the wheels in?

[switz]

Note that the sidewall pressure of the Michelin LTX (P) 235/75R15 XL tire of 2,183 pounds @ 50 psi must be derated to 1,985 pounds load for trailer use.

****************************************

49 CFR 571.110
Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of 4,536 kilograms (10,000 pounds) or less.

S4.2.2.1
Except as provided in S4.2.2.2, the sum of the maximum load ratings of the tires fitted to an axle shall not be less than the GAWR of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. If the certification label shows more than one GAWR for the axle system, the sum shall be not less than the GAWR corresponding to the size designation of the tires fitted to the axle.

S4.2.2.2
When passenger car tires are installed on an MPV, truck, bus, or trailer, each tire's load rating is reduced by dividing it by 1.10 before determining, under S4.2.2.1, the sum of the maximum load ratings of the tires fitted to an axle.

S4.2.2.3
(a) For vehicles, except trailers with no designated seating positions, equipped with passenger car tires, the vehicle normal load on the tire shall be no greater than 94 percent of the derated load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.
(b) For vehicles, except trailers with no designated seating positions, equipped with LT tires, the vehicle normal load on the tire shall be no greater than 94 percent of the load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.

************************************************

Thus two Michelin LTX (P) 235/75R15 XL tires are rated less than the 4,500 pound axle rating at the full side wall number of 2,183 pounds let alone the required lower use number of 1,983 pounds.

I would suggest that individual wheel weights be obtained and certified at your maximum loaded condition going camping as proof the individual tires were not overloaded in case of a failure resulting in damage to the trailer. Insurance companies have no trouble collecting premiums, but they look for ways to weasel out of paying claims. A knowingly overloaded tire condition could allow them to walk away from paying let alone being below the axle rating.....

Airstream installed on 2014 and earlier Classics with 5,000 pound rated axles the GYM ST225/75R15D rated 2,540 pounds @ 65 psi. So the weak link was the axle.

I upgraded our 2014 31' Classic to the Michelin LT225/75R16/E LTX M/S2 tires rated 2,680 pounds @ 80 psi and mounted on the SenDel T03-66655T wheels rated 3,580 pounds @ 80 psi. These tires and wheels are on display at the entrance to the Airstream Service Center at the factory and approved for all dual axle trailers 25' and longer and installed on the Eddie Bauer models and 2015 and later 30' and longer Classics.

[Lance M]

A point on pressure that I learned here-
The pressure that the Michelin LTX M/S2 P235/75R15XL 108T carries its rated load is 41 PSI. The maximum pressure is 50 PSI. There is no load capacity increase above 41 PSI.
Tire Tech Information - Tire Specs Explained: Maximum Load

[franklyfrank]

Originally Posted by mrprez

Did you take the trailer to the tire dealer to get them mounted or did you just take the wheels in?

I drove the trailer to Tire King and had the tires switched out. They had to order the 15" tires because it is not a stock item.

[Rocinante]

If I took the 4,500 rating per axle seriously, I'd think I could load up the trailer until it weighed 9,000 pounds. However, the max permitted gross weight is 7,600. Thus, it seems the axle ratings are mostly irrelevant to this discussion. That said, weighing the trailer to be sure of the weights to ensure I don't exceed the tire rating (or de-rating) on any wheel or axle is sound advice.

[switz]

The 2013 30' International mentioned in post #106 has a GVW of 8,800 pounds. The two axles are rated 4,500, pounds each. Two of the installed derated Michelin LTX MS/2 P235 R/15 tires have a combined payload less than their axle rating. So the operator is in violation of article S4.2.2.1 of 49 CFR 571.110 mentioned in post #109 above.

Insurance companies could walk away from paying a claim citing willful negligence or something similar for undersized tires for the axles. The operator would need certified scales proof of each tire's load to try and counter that argument. Just saying...

[Tireman9]

Originally Posted by Top

A point on pressure that I learned here-
The pressure that the Michelin LTX M/S2 P235/75R15XL 108T carries its rated load is 41 PSI. The maximum pressure is 50 PSI. There is no load capacity increase above 41 PSI.
Tire Tech Information - Tire Specs Explained: Maximum Load

Thanks for the facts. I was wondering about the oft stated 51 psi when 41 is the normal max associated with XL passenger tires.
I was assuming that when this tire topic was started the information on Load and Inflation was being correctly reported.

As I have previously reported the numbers associated with the "complete" size nomenclature are very important. When discussing Load and inflation it should eb easy to read the tire as the max load and the inflation needed to support that load are clearly stated together.

There is also a "Safety warning" on many passenger and LT tires that includes a statement about "max inflation" but that number is really the max pressure that should ever be used when inflating a tire to ensure proper seating of the tire bead against the rim. This number is not associated with the load carrying capacity of the tire.

Here is a sample Safety Warning from a Performance 16" passenger tire



Here is the Load and inflation information, again for a passenger tire



Now while the above are from a passenger tire that was convenient for me to get pictures of, I know that you should see similar on your ST or LT type tires.

I think you may learn a bit more about your own tires if you take a moment to read the information provided. Knowing what tires say on the sidewall can help avoid making mistakes when assumptions are made.

[Rocinante]

Fair enough, I guess. However, as the OP, I was posting about the potential of using these tires on an International 27FB with a GVW of 7,600 pounds. I would not use them on a trailer with a GVW of 8,800 pounds on two axles.

Thanks!

Originally Posted by switz

The 2013 30' International mentioned in post #106 has a GVW of 8,800 pounds. The two axles are rated 4,500, pounds each. Two of the installed derated Michelin LTX MS/2 P235 R/15 tires have a combined payload less than their axle rating. So the operator is in violation of article S4.2.2.1 of 49 CFR 571.110 mentioned in post #109 above.

[franklyfrank]

Originally Posted by Top

A point on pressure that I learned here-
The pressure that the Michelin LTX M/S2 P235/75R15XL 108T carries its rated load is 41 PSI. The maximum pressure is 50 PSI. There is no load capacity increase above 41 PSI.
Tire Tech Information - Tire Specs Explained: Maximum Load

Your comment is incorrect and misleading.
The load capacity of 2,183 LBS at 50 PSI is stamped right on the tire.
The XL designation is extra load. There are a number ST tires manufactured with dual D and E load capacities at 60 and 80 PSI respectively.

My loaded 30' International never exceeded 6,800 LBS the way we travel, and that is constant over the last 3 years. That is with the water tank close to full. With the Blue Ox WDH the dual axle loading on the trailer increases to the max of 7,100 LBS. aprox. 1,775 LBS per wheel within specs and reasonable safety expectations.
In my younger days I drove Gasoline and Chemical tankers for a number of years. In my own construction business I operated 25 Semi Dumps for 30 years. I am more than a little acquainted with vehicle weights, trailer loading and tire safety.

[Lance M]

Originally Posted by franklyfrank

Your comment is incorrect and misleading.
The load capacity of 2,183 LBS at 50 PSI is stamped right on the tire.
The XL designation is extra load. There are a number ST tires manufactured with dual D and E load capacities at 60 and 80 PSI respectively.

Frank,
Sorry, but you obviously didn't read the link in my post or the post from Tireman9, a tire engineer.

Yes, the tire is stamped with 50 PSI MAX, but that is not the pressure it obtains the maximum load capacity. That pressure is 41 PSI.

Here is a post when Capri Racer, another tire engineer, educated me on the 41 PSI issue.

[Lucky Dog]

Max load at 41 psi brought up in my post #20. Just sayin'.....

[switz]

The axles on the 25' to 27/28' Airstream International trailers are rated 3,800 pounds per the Airstream parts manual.

Thus two Michelin LTX (P) 235/75R15 XL tires sidewall rated 2,183 pounds @ 50 psi but derated to 1,985 pounds for trailer use exceed the axle rating by more margin than the two factory installed GYM ST225/75R15D tires rated 2,540 pounds @ 65 psi installed on the 5,000 pound axles of my 2014 31' Classic.

The 16" Michelin LT225/75R16/E LTX M/S2 tires rated 2,680 pounds @ 80 psi I installed on our Classic have more load margin than the stock GYM ST225/75R15D tires and these Michelins are now standard on 2015 and later 31' Classics.

No matter what the scale ticket says, the two Michelin LTX (P) 235/75R15 XL tires sidewall rated 2,183 pounds @ 50 psi but derated to 1,985 pounds for trailer use are under rated for the 4,500 pound axles used on the 30' trailers with GVW of 8,800 pounds. The insurance company could be legally correct for denying a tire related claim citing:

***********************

49 CFR 571.110

Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of 4,536 kilograms (10,000 pounds) or less.

S4.2.2.1

Except as provided in S4.2.2.2, the sum of the maximum load ratings of the tires fitted to an axle shall not be less than the GAWR of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. If the certification label shows more than one GAWR for the axle system, the sum shall be not less than the GAWR corresponding to the size designation of the tires fitted to the axle.

S4.2.2.2

When passenger car tires are installed on an MPV, truck, bus, or trailer, each tire's load rating is reduced by dividing it by 1.10 before determining, under S4.2.2.1, the sum of the maximum load ratings of the tires fitted to an axle.

S4.2.2.3

(a) For vehicles, except trailers with no designated seating positions, equipped with passenger car tires, the vehicle normal load on the tire shall be no greater than 94 percent of the derated load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.
(b) For vehicles, except trailers with no designated seating positions, equipped with LT tires, the vehicle normal load on the tire shall be no greater than 94 percent of the load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.

************************

Andy at CanAm suggested running the 15" Michelins at 44 psi on both my 25FB and the 23D.

The Michelins are my tire of choice for my trailers and four tire vehicles.

[Bill M.]

Read franklyfrank again.

He is stating what is actually stamped on the tire in question. Mine also have the "load" at 50 psi stamped on the sidewall. They are 650 miles away right now but I checked the last time we had this discussion.