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

[Bill M.]

The Michelins mentioned at the start of the thread are a p- tire. They would have to be a LT tire to be a load range C. Yet the maximum inflation pressure for the XL is 50 lbs, the same as for load range C. Michelin used to make a 15" LT load range C and the 15" XL tire. They dropped the LT load range C.

[switz]

Per federal regulation, all trailers must be weighed as they come off the assembly line. So if two air conditioners with 50 amp service and or street side and rear awnings were installed on the line, that weight reflects those accessories.

The Michelin LTX (P) 235/75R15 XL tire is sidewall rated 2,183 pounds @ 50 psi. For non-car use (meaning trailer) it must be derated to 1,983 pounds load capacity per 49 CFR 571.110. I used this tire on our 2013 25FB International Serenity where the axle load camping ready was 5,860 pounds, which was well within the load capacity of the tire. The right rear (curb side) carried about 200 pounds more weight than the other three tires.

I also installed this tire on our 2015 23D International Serenity that has a GVW of 6,000 pounds. I have not had the time to weigh the individual wheels on my sets of scales, but there is an adequate safety margin as the axles were carrying about 5,500 pounds.

[Jim & Susan]

Originally Posted by SteveSueMac

Have you weighed your trailer? I have to assume a 73 27 footer is lighter than my wide body 2012 27 footer. Loaded for camping it's about 6000# on the scales and plenty of room for the lower capacity Michelin (these ones the OP listed have about another 70#s per tire). Even I f your trailer is as heavy as mine, you would have plenty of load capacity.

Yup. Right now, as it sits today, it comes in at about 3600 lbs....but, it's not done yet. I may hold the record for the longest restoration on the planet.

I expect another 1000 lbs or so (maybe, and that's being generous on the high side).

I'm not worried about it being too heavy in comparison to modern Airstreams. The published max weight when new was only about 6300 lbs.

I should be good on the weight end of it. I'm more concerned about sidewall strength because of all the inevitable curbs and things we all encounter.

Make sense? "Trailer Tires" are "cheap". One doesn't have to an be engineer to figure that out. Just look at them next to a regular truck tire. The simply look "cheap". Tread depth is shallow and there's a lot of room between the lug surfaces (the part that touches the road) and the main carcass of the tires. New Michelin's look like a "more dense" tire. I'll take more rubber over cheap any day.

Just my ill-educated opinion.

Jim

[Jim & Susan]

Just noticed Andrew T is reading this thread right now.

Go for it Dude. Your opinion is valued and respected. Please weigh in.

Jim

[Caroyl]

I've seen some talk here since starting the search for our vintage AS. We recently bought a 1964 Overlander LY which will need new tires and aluminum wheels before the full renovation is finished and she is ready to roll. We are thinking we'll go with 16" wheels and LT tires, but I have no idea what the specs to shop for. Also, I'm seeing the nearly new 15" sets being sold on the forums and that's tempting. Of course I can't buy new or used unless I know what we have/need. Anyone know what size/configuration is used in the '64?


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[switz]

I forgot to mention that the scaled weight just off the production line is printed on the white label on the street side front panel of the trailer along with the tire data and specifications and VIN. The net payload based upon the weight just read also generates the yellow tag number seen on the screen door.

If the 16" tire option was ordered, that conversion is done at the service center after coming off the line. That means the weights were determined with the lighter GYM ST tire and not the heavier 16" Michelins. So the weigh tag is immediately incorrect for the presumed empty weight with larger tires.

[Tireman9]

Originally Posted by Bill M.

The Michelins mentioned at the start of the thread are a p- tire. They would have to be a LT tire to be a load range C. Yet the maximum inflation pressure for the XL is 50 lbs, the same as for load range C. Michelin used to make a 15" LT load range C and the 15" XL tire. They dropped the LT load range C.

This points out the importance of paying attention to the complete tire size and Load Range.
Most XL P type tires are rated for 41 psi
P Type tires come in Standard load (no mark or letter) and Extra Load or XL
LT tires do not need to be de-rated as P type tires do when on a TT and LT tires would normally have Load Range C, D or E although there are some exceptions.

Remember that just because one tire company makes a "non-standard" tire does not mean other brand or even other design tires from the same company would have the same load or inflation capability.

Check out THIS post if you want to see why the complete size can make a lot of difference.

[Lance M]

The new Michelin Defender LTX M/S 235/70/15 109T XL is a "Euro-metric" sized tire, not the "P" designation tire it replaced. None of the new Michelin Defender LTX M/S tires are "P" tires. Kind of strange to me, but I guess this is a new trend in tires. GoodYear Wrangler All Terrain Adventure tires are designated the same way.

From Tire Rack-
"If there isn't a letter preceding the three-digit numeric portion of a tire size, it signifies the tire is a "Metric" size (also called "Euro-metric" because these sizes originated in Europe). While Metric tire sizes are primarily used on European cars, they are also used on vans and sport utility vehicles. Euro-metric sizes are dimensionally equivalent to P-metric sizes, but typically differ subtly in load carrying capabilities."

I'm not sure what difference it makes, but the absence of the "P" on the sidewall may make a few Airstreamers a bit more comfortable using this tire.

[xrvr]

Seems like I read somewhere that if the tire had LT at the end of the designation it could be used as a trailer tire. As opposed to LT being in the front. Anyone of the experts care to comment? Just curious.

[Rocinante]

This post from Tireman9 on his blog may be of interest regarding what LT in a tire name means - whether it's a "design name" or a size/load designation. RV Tire Safety: LT

Since we're not tire people, we're guessing the "LT" in this tire is a "design name." We think that means we'd need to do the "10% de-rating" thing to calculate a safe load for these tires. e.g. the "109" in this tire means it is rated at 2271 lb for cars, SUV's etc., and after the 10% de-rating exercise a safe trailer load for this new tire would come in at 2044.

The max gross weight for our 27FB trailer is 7600 and 4 of these tires would handle a total load of 8176. That's a 7.5% safety factor for a maximally loaded trailer, assuming all tires are carrying the same weight. (BTW, we know it will *never* be true that all tires are carrying the same weight, and that our trailer fully rigged for camping comes in around 6,500.) So, we feel pretty comfortable, based on the numbers, with the idea that these new tires could work well for our trailer on our existing 15" wheels.

Come spring, when these tires are scheduled to be available, we'll probably give them a try. We'd be hoping to get our 2 -3 year old GYMs off the trailer before we have an incident, without tossing a perfectly good and handsome set of wheels.

[kscherzi]

Originally Posted by Rocinante

The max gross weight for our 27FB trailer is 7600 and 4 of these tires would handle a total load of 8176. That's a 7.5% safety factor for a maximally loaded trailer, assuming all tires are carrying the same weight. (BTW, we know it will *never* be true that all tires are carrying the same weight, and that our trailer fully rigged for camping comes in around 6,500.) So, we feel pretty comfortable, based on the numbers, with the idea that these new tires could work well for our trailer on our existing 15" wheels.

Remember, of the max 7,600 lb allowable, somewhere between 700 and 1,000 lbs of this will be carried by the tow vehicle via the hitch. On a CAT scale loaded for camping with a full fresh water tank, my 27FB came in at 6,000 lbs total on the axles. Using a Sherline scale the hitch weighed in at 900 lbs for a combined total of just under 7,000 lbs. Since the tires will probably always be carrying less than 6,500 lbs maximum, these tires should work out just fine.

[DoublTrouble]

Roc & kscherzi

We're in the same boat
following along,
Our 27FB IS 6880 # total. 1000# of which is on the on the tongue. I'm torn on this issue. For sure, come spring, I need TPMS and at least brass stems. These tires do look promising.

[DoublTrouble]

BTW
Similar discussion here
http://www.airforums.com/forums/showthread.php?t=125637
Pg 127ish

[Mrjkq]

I've spent the last two afternoons online researching this issue. I have no faith in GMT, but changing out new 2016 cast aluminum rims did not sit right, I felt their had to be a better alternative & found one. This contender tire won't surface until March but it offers a solution for me & I'm going to roll the dice & place an order.

[A W Warn]

I'm posting so I can follow this discussion.
It looks like the Michelin Defender 235 75 x 15 will work on both my 25' and 34'.
I'll need new tires before the summer travel season on my 25'.

[kscherzi]

I'll be getting new tires too. My Marathons are over 3 years old at least with near 10,000 miles. Don't know manufacturing date. Three years seems to be when blowouts start.

By the numbers my 27FB should carry no more than about 1,800 lbs per tire worst case. Loaded for camping full fresh water the CAT scale said 6,000 lbs or 1,500 average per tire last time I weighed it. De-rated at just over 2,000 lbs for towing the 15 inch Defender ought to work just fine.

Here's a link to a blog on 15 inch Michelins that's informative. http://maze.airstreamlife.com/2015/0...ut-everything/

[sunahara]

LT means light truck duty, I believe

[franklyfrank]

Originally Posted by avionstream

Seems like I read somewhere that if the tire had LT at the end of the designation it could be used as a trailer tire. As opposed to LT being in the front. Anyone of the experts care to comment? Just curious.

LT means Light Truck, LTX designates Light Truck Extra load.
I have these Michelins on my 30' International 15" LTX - 108T high speed. They are awesome tires. At 50 PSI they are rated for 2,150 lb.
I can cruise at 70 MPH and not have any anxiety about trailer tires separating.
Hardly ever have to add air like with the crapola Goodyear Marathons AS installs on these expensive trailers.

[Ridgerunner3]

I am sure the Defenders will be a great addition to the potential AS tire population. I have been running the Michelin LTX P235 75 15 XL's on my 2002 Safari 25 for 15,000 miles. I run 44 psi per Andrew T's recommendation. They are a great tire. I have run Maxxis and Goodyear in the past. Only Michelin from now on.

[xrvr]

Ltx, light truck extra load?? Huh?