A friend of mine just called and asked if I could ask you guys about a tire issue he's having. He is in his Class C, on a trip between CA and OK, and has blown a tire. He knows that he's due for new tires, but is having some issues with locating the Michelin XPS Ribs (10 ply "E" rating, with metal mesh sidewalls), which apparently have to be special ordered for his RV. The Tire store recommended the LTX-M/S tire, with the same ratings, but it doesn't have the metal sidewalls.Is it really going to make a difference? He doesn't mind the extra money, if it's a safer tire having the metal sidewalls. Of course, it is ironic that the tire with the metal sidewall is what blew out when he hit one of California's many potholes!!He's on the road, so I'm going to send him texts of your comments. He knows he's going to be buying new tires all the way around on his RV (save that new tire as a spare), but wants to make the smart/safe choice. He's got basically the same RV as I do (31' Winnie), so I'm also interested.:)What would you recommend. I know that I probably should have posted this in the technical forum, but when I looked there, most of the tire stuff was for P/Us and trailers...not much for a Class C.Thanks in advance.

I chose Michelin XPS RIBS after researching various forums for a few months. The one forum is used by drivers who transport vehicles and goods using medium duty trucks. Many of them travel 100,000 to 300,000 miles per year and will go through numerous tires. Quite a few used the XPS RIBS because the tires held up well and provided more than expected miles of trouble free use.That being said, I don't think I would want to sit around and wait for tires for more than a day or two if time was an issue or I didn't like where I was stuck.

If you bought a new Class C on a Ford chassis, it'd come with Michelin LTX M/S2 tires. Michelin is a name that needs no introduction, no apology, anywhere in the world. The LTX M/S2 meets all requirements and has that reputation for quality. The XPS RIB is a downsized commercial tire. So is Bridgestone's Duravis R250. Same load rating but the tire is considered "tougher." Our Class C had R250's from the previous owner. They were bulletproof, so when we needed to replace, we simply went with another set. Discount (aka America's) Tire.Does your friend care that LTX has an "all season" tread and XPS has a "highway" tread? I've heard it claimed that a "Rib" or "Highway" tread is similar to "Steer Axle" tread for heavy duty trucks. They use "Steer, "Drive," and "Trailer" versions of their big tires, like the 22.5" and 24.5" rim sizes. Anyway, some believe that Rib will track better on the road than All Season. We had All Season on or first Class C and it tracked fine.

any good tire dealer should be able to get you what YOU want in a day.

Make sure they are M/S2 and not just M/S tires. Ribs are best have call a Goodyear Commercial Truck Store. Think that they are called G/Y Wingfoot stores. They might have them in stock.Don

I'm the OP of this thread dealing with M/S.https://forums.woodalls.com/index.cfm/fuseaction/thread/tid/28750800/gotomsg/28751364.cfm#28751364I'm not impressed with the wear of M/S and wish I'd would of known before buying them. They're built for traction not wear, my understanding.

Tires: XPS Ribs vs. LTX M/S? | Good Sam Community

18 Replies

RambleOnNW
Explorer II
Feb 27, 2016
Pnichols:

Good point on the LT215/85R16 option. A possible tradeoff of a 1/2" of increased ground clearance with a taller sidewall and therefore more sidewall flex. I may have to think about that when my current tires age out.

Treadwear is not an issue for me. The tires will age out before the tread wears sufficiently such that they are worn out.

The G947 are likely around $300/tire + mounting and balancing which is more than what I paid for the all-steel casing Bridgestone Duravis M895 M+S that I have been running for 2.5 years. I bought through Les Schwab for their dealer network support so there was some additional markup included.

Here is a set of 6 of the G947 at Ebay for $312, no date codes listed though. As usual look for tires that are 6 months old or newer. The same place has a website that has the tires for $261 + $30 shipping to the PNW, http://www.giga-tires.com
F1bNorm
Explorer
Feb 27, 2016
Years ago, I learned it is important to buy tires from a dealer or chain that has a good tire exchange/satisfaction agreement. A couple years ago I replaced the aged out Mich LTX with the newer LTX 2 and my rig squirmed all over the road. Brought it back and they suggested I try the XPS Rib. The exchange was no big deal and I was satisfied with the result.

I realize your friend is on the road so whatever choice he makes, use a dealer chain popular in that region. For me, in SoCal, it was America's Tire.

Norm
pnichols
Explorer II
Feb 27, 2016
RambleOnNW,

Thanks much for that link you provided to the G947 tire. It's a bit non-intuitive to get to starting from the main Goodyear website.

Note that they emphasize the steel as being primarily for sidewall and shoulder scrub resistance and the capability for commercial use retreading.

It appears to be a superior tire to the LTX M/S2 (the long mileage warranty, Green X rating, and maybe no-crack sidewalls of the M/S2 notwithstanding) since it sports a mud and snow stamped tread. IMHO, it's also a superior tire to the Michelin XPS Rib tire for RV use due to it's more practical mud and snow tread.

I notice that it even comes in my preferred Class C Load Range E size of LT215/85R16 ... to provide for around 0.6 inches of additional ground clearance over the common but less tall LT225/75R16 size.

You have to be able to deal with the G947's stratospheric price, though, while accepting that you're probably getting less tread wear mileage for your money.
RambleOnNW
Explorer II
Feb 27, 2016
Goodyear G947 is still shown on the Goodyear commercial truck tires site. That is what I plan to go to when the current Bridgestone Duravis M895 M+S age out.

Goodyear G947 RSS Armor Max
j-d
Explorer II
Feb 27, 2016
Bridgestone Duravis R250 has steel. The other tires in the Duravis lineup do not. R250 is "highway" or "rib" tread. There was a Duravis traction tire with steel but no longer. It's more like a Michelin M/S2.

We used to say there were three ruggedized tires in Class C sizes. The XPS RIB, R250, and that Goodyear G947. From what Phil says, there may now be only two, from Michelin and from Bridgestone.
pnichols
Explorer II
Feb 26, 2016
I run 80 lbs. of pressure in my Class C rig's rear duals with the M/S2 tires. This keeps any sway from the tires being noticeable. My Class C is only 24 feet, so I've never had any rear end sway problems.

The M/S2 tires use a different sidewall material than that of the previous M/S tires. I don't know about the material being softer ... what I'm hoping for is that the new material stops the notorious premature sidewall cracking that the M/S tires were noted for.

I researched the Goodyear G947 tires at my last Class C tire change. They were very expensive and hard to find even back then in Class C motorhome sizes. They may be discontinued now ... at the very least you sure can't locate them easily at the Goodyear website. I believe that the G947 tire only has steel in the sidewalls - not in the tread area (just like with the XPS Rib tire). What I wanted was a tire that also had steel in the tread area for best off-highway puncture protection ... which I guess doesn't exist anymore. What ultimately sold me on the new Michelin M/S2 was their 70,000 mile warranty, their Green X rating, and the possibility that their sidewalls might not crack prematurely due to the new sidewall material.
egrove
Explorer
Feb 26, 2016
The M/S2 tires have softer sidewalls than the original M/S tires. I know as I have had both. The new M/S2 tires cause the motorhome to sway more given the softer sidewalls. If I knew this I probably wouldn't have bought them.
RambleOnNW
Explorer II
Feb 26, 2016
As pointed out all LT225/75R-16 tires have to meet the tire safety tests, which are covered by NHTSA FMVSS 139:

http://www.nhtsa.gov/DOT/NHTSA/Vehicle%20Safety/Test%20Procedures/Associated%20Files/TP-139-02.pdf

This covers such tests as tire endurance, puncture resistance, running under inflated, etc.

What the tests do not tell you is how much design margin the tires have, the tires are not stressed to failure and results reported.

The tires vary in weight, for example an LTX M/S2 tire weighs 39 lbs per tire, and an XPS Rib weighs 49 lbs. per tire. I take tire weight to be a proxy for design margin and that is why I have all steel cased tires.

Another choice for all-steel cased tires with M/S capability is the Goodyear G947 RSS Armor Max.
pnichols
Explorer II
Feb 25, 2016
You can see here that the regular Michelin XPS Rib tire is intended for commercial applications on the road, as is indicated by it's real smooth highway tread. It's warranty is only 60,000 miles:

http://www.michelinman.com/US/en/tires/products/xps-rib.html

If you would like your Class C to really be "ready for any road surface", then you might want to consider this Michelin XPS Traction tire (still with a steel casing) instead - if it's tread does not create too much noise on hard surfaces. However, it's warranty is only 50,000 miles:

http://www.michelinman.com/US/en/tires/products/xps-traction.html

Note that the Michelin LTX M/S2 tire has a 70,000 mile warranty. Of course no one would keep the same set of tires on their Class C for anywhere near 70,000 miles, but what this warranty means is that at whatever mileage you have on your LTX M/S2 tries, their tread is probably going to be less worn (for safer traction and more puncture-proofness) than that of tires with a lower warranty at the same mileage. The M/S2 tire carries this long warranty despite it's mildly aggressive mud and snow tread:

http://www.michelinman.com/US/en/tires/products/ltx-m-s-2.html

It's too bad that Michelin doesn't offer a mud and snow tire with a steel casing and a 70,000 mile warranty!
VA-Apraisr
Explorer II
Feb 25, 2016
I have the rib XPS and does great in soft sand, snow and heavy rain.....10 thumbs up on these tires!!!!!!!