Tread Separation on Michelin LTX225/75R16(E) M+S2

[blkmagikca]

Tireman9 -> Re free wheel spin test, I have JC check my running gear twice each year - on my way south to AZ and then again on my way home. In my younger days I crawled under my vehicles and did my own maintenance, but as an arthritic 77 year old, I have JC dof it for me. They have in past found tread separation for me on 2 occasions when I had the 15" ST tires.

[Troutboy]

I keep searching for the tireman blog, but the rvtiresaftey site seems to require a domain renewal....

[Ted S.]

When I bought my Airstream I was offered a $2500 upgrade to go the Michelins. So how can they offer them if they are a misapplication ?

I ended up upgrading on my own for a lot less money.

[dznf0g]

Originally Posted by Ted S.

When I bought my Airstream I was offered a $2500 upgrade to go the Michelins. So how can they offer them if they are a misapplication ?

I ended up upgrading on my own for a lot less money.

Hmmmm, $2500 for $1100 worth of parts.

[PharmGeek]

I was told by dealer originally 2500

Then I found someone else who paid 1700

I demanded that

It's all part of the same negotiation price game buying :/

[dznf0g]

Originally Posted by dznf0g

Hmmmm, $2500 for $1100 worth of parts.

um, and I forgot the value of the no charge OE tires and wheels. I suggest getting the 15" setup, buying the tires and wheels for $1100ish and selling the brand new OE tires and wheels for $400 - $500. Mount and balance for $80ish...so your cost = $680 - $780

[PharmGeek]

Clearly a more economical way

If/when I buy again that's what I'll do

[dznf0g]

Originally Posted by PharmGeek

Clearly a more economical way

If/when I buy again that's what I'll do

Then put that $1k into the college fund for the cute little carpet crawler in your avatar!

[CapriRacer]

Originally Posted by Troutboy

I keep searching for the tireman blog, but the rvtiresaftey site seems to require a domain renewal....

http://www.rvtiresafety.net/

[Troutboy]

Thank you!!!

[Ted S.]

I did do the upgrade and sold my stock tires and rims. I think all in it cost me $900.

One thing that crossed my mind is that if you have the factory do it, the upgrade is documented within the trailer paperwork. There maybe some value to that.

[rodsterinfl]

@Ted S. I did the same- sold the old. My purchase was about $600 for the tires and $440 for the wheels. I got the tires at Same but they made me sign a waiver when they installed them on the trailer wheels. Then I paid for load balancing and install. I do not think I could have done much better price-wise. I sold the old for about $150.

On the warranty, more and more trailers have these tires.

On the PSI- note that the safety link refers more than once to the tire's load/PSI table. That is what I have shared many times on the forum but many believe you should just pump em to the max for side shear reasons.

[Ted S.]

Yes, I run them at 80 psi. I am very happy with them.

[Countryboy59]

When I ordered my 25' the option was $1000. Guess it depends on the dealer

[Andrew T]

Hi Ted. 80PSI is going to be a very harsh ride for the Airstream. On your Airstream 55 psi will be close to the correct pressure. If you want to be sure you can weigh the Airstream and then get the pressure from load inflation tables.

[Tireman9]

Originally Posted by Andrew T

Hi Ted. 80PSI is going to be a very harsh ride for the Airstream. On your Airstream 55 psi will be close to the correct pressure. If you want to be sure you can weigh the Airstream and then get the pressure from load inflation tables.

While it is true that you can sense harsh ride Have you collected any meaningful data ph how much difference there is for different inflations?

Have you confirmed that 55 is sufficient to carry the actual load on the heaviest loaded tire?

Are you really willing to give up 1 or 2 years tire life due to more likely early failure due to belt separation because of higher Interply Shear?

[blkmagikca]

Payment received from Michelin - case closed!!

[Troutboy]

Originally Posted by blkmagikca

Payment received from Michelin - case closed!!

Congrats, thanks for sharing and closing it out.

[OTRA15]

Ditto, thanks.

[JamuJoe]

Originally Posted by switz

This Federal Regulation spells out the procedure for using these 15" Michelin LTX (P) 235/75R15 XL tires on a trailer.



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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 my 15" Michelin LTX (P) 235/75R15 XL tires with a sidewall rating of 2,183 pounds @ 50 psi are derated to 1,985 pounds payload for trailer use.



The numbers for our 2015 23D International Serenity loaded for camping are:



Camping Ready 23D my scales 9 May 2016



Tongue………928

Front….1,280……1,246 - total front axle 2,526

Rear…..1,376……1,233 - total rear axle 2,609

Total Axles………5,135

Total Trailer….6,063



Each of my 15" Michelin tires are derated to 1,985 pounds load capacity so there is still a 31% load margin for the heaviest loaded tire. They still work for the typical 25FB model as well.



We run 44 psi which is still the maximum load point for the tire. One gets a softer ride and larger tire foot print for braking as compared to the stock GYM ST tires.



For comparison, the stock 14" GYM ST215/75R14C tires were rated 1,870 pounds @ 50 psi for the 23D models up to 2017 when Airstream upgraded the 23D trailer models to the 15" GYM ST tires since the 14" tires are going the way of the Dodo bird.

Thank you Switz! Real data is much appreciated. My loaded 2011 23FB is a bit lighter:
Tongue785
Right Front1260
Left Front1332
Front Axle2592
Right Rear1187
Left Rear1109
Rear Axle2296
Total Trailer 5673
My 15" Michelins are in great shape at 32,000 miles . I run them at 50psi. Had one road hazard blowout, otherwise excellent performance.

Safe Travels,
JamuJoe