365/70R-22.5 Steering Tires on 2020 Cornerstones

[BigKahuna]

While traveling to a race in Indy the curbside steering tire on my 2020 Cornerstone came apart and beat the Hell out of my coach. More specifically, the tire edge piece vulcanized between the sidewall and the tread broke off and then the sidewall became unglued.

Coachnet spent 3 hours trying to locate something for me because the Michelin 365/70R-22.5 are on National back order with no date on when/if ever available again. They located me a nasty used tire in another state for $500 plus installation. They paid $545 to get it delivered to me.

Once the roadside tire guy left, I saw a piece missing on the same edge piece of that tire. Then while filling up with diesel I noticed a piece missing out of the same edge of the steering tire on the street side of the coach. I'm not a big believer of a coincidence that three out of three tires are missing a chunk off the edge AND the tire is not only unavailable -- but there's no date projected on when they will be. Sounds to me like they know of a problem but the Highway Safety Board doesn't yet.

At the track, my two closest friends who had Entegras now have Tiffen Zephyrs the same length and 605hp Cummins as my Cornerstone - but Tiffin builds their own chassis instead of using a Spartan.

I looked at their steering tires and they have 315s rated at 8750 pounds load - while my 365s are rated at 10500 pounds load - almost 20% less load rating. I have no idea what the axle rate is on either of our coaches. I also noticed that the wheel's bead lip is a little different between mine and theirs.
I drove the 1200 miles home at 10-miles under the speed limit after searching the net and seeing a problem on steering blowouts -- and even an armour company making run flat inserts specifically for Spartan chassis with the 365 tires. They even referred to the rims as "365 Wheels", making me believe that they're specific to Spartan with 365 tires.

I need to resolve my problem quickly - as I use this coach for traveling across the country running in a drag racing series.

Questions:

1. Is there a known problem with these tires?
2. Is there a recall on these tires?
3. Since Spartan and Entegra can't get these tires either (unless that's where they all are) -- what are you using on the Conerstones?
4. I see people posting that they're putting on the lower load rated 315s and running less air. That doesn't sound safe to me if there's a requirement of a steering tire over 8750 pounds.
5. Is there a safety requirement (like axle weight) requiring the use of these 365 tires?

6. If there is another tire I can replace the 365s with, can it safely be on this rim that is being called a "365 Wheel"?
7. What air pressure does Spartan Suggest on the 365 and the tire I need to locate to replace them. I've been running 120 Cold and the dash gauge shows the pressure and temp in the green.

[Poppedclams]

I will not try and put a product down. I will either not use it or I will. I did just remove the oem Michelin tires and replaced with a different brand. I was told and shown there was ribbons on all of them. I'm satisfied with the new tires on coach. I will say I would not chance another set doing same. There was 35k on the tires when I changed up.

[BigKahuna]

Originally Posted by Poppedclams

I will not try and put a product down. I will either not use it or I will. I did just remove the oem Michelin tires and replaced with a different brand. I was told and shown there was ribbons on all of them. I'm satisfied with the new tires on coach. I will say I would not chance another set doing same. There was 35k on the tires when I changed up.

My problem is no one else makes a 365 and no one else make a 10,500 load tire. 315 and 8750 the highest load. I'd like to know why Sparton and Entegra need to have a tire that big on the coach

[Petek]

I'm going to keep a close eye on this thread. Had a similar failure 2 years ago on DS steer tire on my 17 cornerstone. Luckily I caught it before it blew and had it replaced. Now I'm wondering how many others have had the same failure?

[Gary.Jones]

My 365s, which have about 50,000 miles on them, look brand new. No problems with them and quality appears to be excellent.

Further, I read this forum carefully, and I have never read a concern with these tires from anyone else that I can remember. If I get my Rettrobands installed, I will likely need to replace with new front tires but I have only considered that I will replace them with new Michelin 365s.

Now, I am not aware of a national shortage of 365s, but that certainly could be true. I would suggest that you get on the phone and call NIRVC at any of their locations (but I would recommend Lewisville or Atlanta) and ask them about availability as they are heavy installers (and exclusive installers) of Rettroband blowout protective devices and see if they have a path to get new tires (I would guess that they can get their hands on them). Also, as a last resort, try Entegra Coach as I know they have them. You should also probably consider having Rettrobands installed in those new tires when you replace them as they are a very impressive product to prevent the serious consequences of a front tire blowout on an heavy coach like a 45' diesel Entegra.

Anyone who replaces 365s with 315s is not using their heads IMO. !!!! That would be dangerous.

Anyone can have problems with a product, but I seriously doubt that this is a common problem with the 365s.

Gary

[RVFunlovers]

I have had good luck with the 365’s on my 17 and 22 year coaches. I am going to be more proactive with inspecting them visually now though.

When I had my coaches weighed the front weight on each side is heavy. To the point where I would not chance using a 315.

I do have retrobands on the front tires.

[777 Driver]

The entegracoach.com website lists the specifications for the 2020 Cornerstone front axle as "Reyco Granning IFS independent 20,000-lb. front axle and air suspension". Putting tires on that axle that can't carry the fulll load limit of the axle doesn't seem like a good idea, to me.

I replaced the steer tires on my '18 Anthem with Michelin X® LINE ENERGY Z COACH 315/80R22.5 that are rated a 9,090 pounds (18,180 pounds) which are adequate for my Reyco Granning axle rated at 17,000 pounds.

As I look at the Michelin website (https://business.michelinman.com/), the only 365 width RV tires are the MICHELIN XZA® 365/70R22.5 that are rated at 10,500 pounds (21,000 pounds).

For the OP, although I'm no tire expert, that's some knarly looking "wear" (damage) on those photos. I think I'd be all over trying to figure out what was causing that.

Take care,
Stu

[BigKahuna]

Originally Posted by Petek

I'm going to keep a close eye on this thread. Had a similar failure 2 years ago on DS steer tire on my 17 cornerstone. Luckily I caught it before it blew and had it replaced. Now I'm wondering how many others have had the same failure?

When three out of three (the two that came with the coach plus the used replacement) have a little bite taken out - I stop believing in coincidence. When the tires are Nationally unavailable with no projected release date - my Spidey Senses tingle. I feel certain that Spartan, Michelin and Entegra all know something they're not telling.

[BigKahuna]

Originally Posted by Gary.Jones

My 365s, which have about 50,000 miles on them, look brand new. No problems with them and quality appears to be excellent.

Further, I read this forum carefully, and I have never read a concern with these tires from anyone else that I can remember. If I get my Rettrobands installed, I will likely need to replace with new front tires but I have only considered that I will replace them with new Michelin 365s.

Now, I am not aware of a national shortage of 365s, but that certainly could be true. I would suggest that you get on the phone and call NIRVC at any of their locations (but I would recommend Lewisville or Atlanta) and ask them about availability as they are heavy installers (and exclusive installers) of Rettroband blowout protective devices and see if they have a path to get new tires (I would guess that they can get their hands on them). Also, as a last resort, try Entegra Coach as I know they have them. You should also probably consider having Rettrobands installed in those new tires when you replace them as they are a very impressive product to prevent the serious consequences of a front tire blowout on an heavy coach like a 45' diesel Entegra.

Anyone who replaces 365s with 315s is not using their heads IMO. !!!! That would be dangerous.

Anyone can have problems with a product, but I seriously doubt that this is a common problem with the 365s.

Gary

I challenge you to do two things:

The first is to try to find one right now from anywhere. You will quickly find out that they are on National Back Order with no projected release date. So say you're 1,000 miles from home and your tire comes apart. What is your plan for that?

Secondly, get a flashlight and carefully have your fingers walk the edge in the first tread groove (1st grove inside and outside) all of the way around the tire. They're hard to see without a detailed inspection. The first tread groove on the inside and the outside on both steering tires.

I'd be interested in what you find.

[BigKahuna]

Originally Posted by RVFunlovers

I have had good luck with the 365’s on my 17 and 22 year coaches. I am going to be more proactive with inspecting them visually now though.

When I had my coaches weighed the front weight on each side is heavy. To the point where I would not chance using a 315.

I do have retrobands on the front tires.

I certainly don't want to replace 10500 pound load tires with 8750 pound load tires. I've spent days on this and there is no solution reported. I emailed both Entegra and Sparton last Wednesday and followed up Friday. Nothing from the Spartan representative assigned to Entegra. Joyce from Entegra emailed me today to see if anyone got to me. I replied No, and she says she's on it.

[Old Scout]

Only guessing but doubt you can even mount a 315 on a 365 rim??? As a start, it would be good to know the front corner weights on your rig.

[BigKahuna]

Originally Posted by 777 Driver

The entegracoach.com website lists the specifications for the 2020 Cornerstone front axle as "Reyco Granning IFS independent 20,000-lb. front axle and air suspension". Putting tires on that axle that can't carry the fulll load limit of the axle doesn't seem like a good idea, to me.

I replaced the steer tires on my '18 Anthem with Michelin X® LINE ENERGY Z COACH 315/80R22.5 that are rated a 9,090 pounds (18,180 pounds) which are adequate for my Reyco Granning axle rated at 17,000 pounds.

As I look at the Michelin website (https://business.michelinman.com/), the only 365 width RV tires are the MICHELIN XZA® 365/70R22.5 that are rated at 10,500 pounds (21,000 pounds).

For the OP, although I'm no tire expert, that's some knarly looking "wear" (damage) on those photos. I think I'd be all over trying to figure out what was causing that.

Take care,
Stu

Sadly those MICHELIN XZA® 365/70R22.5 tires are the only 10,500 steering tire made by any tire manufacturer. They are made out if Unobtainium. As of right now, if you are 1000 miles from home and need one - you're screwed. My coach is parked until I can get this resolved - and there appears to be no available resolution. Fortunately, drag racing season is over until February for me. However, until this is resolved a set of tires keeps me from driving my half-million dollar coach. I'm not happy.

I challenge everyone with MICHELIN XZA® 365/70R22.5 to inspect every inch of the 1st (outside) and last (inside) tread groove of their steering tires. You obviously need to have someone inch the coach forward with tire fully turned to inspect the inside tread all of the way around. It starts coming apart after just 2 inches of the tread groove getting wider. That's enough for the edge piece to start to become unglued, and at 70mph the entire edge to come apart from centrifugal force and whip the Hell out of your coach before exiting. Within a couple miles (of pulling off the highway) after that, the sidewall unglues starting at where the edge was.

[BigKahuna]

Originally Posted by Old Scout

Only guessing but doubt you can even mount a 315 on a 365 rim??? As a start, it would be good to know the front corner weights on your rig.

That was part of my question to Spartan and Entegra. No way I'm doing anything until I get their official word of the solution they're using and will stand behind. They need to be doing something with that Spartan Chassis if those tires aren't available. Either they have every last tire so there are no replacements, they've changed the tire they put on, or they are not building that chassis at the moment.

If I had a coach with that tire as the only spec, I'd want to know what kind of trouble I'll be having it if I need to replace my tire on the road. I was able to get to a Walmart, gave Coachnet spend three hours locating a used tire from another state and pay $545 to have it driven to me, so I could pay $500 plus installation and tax to put it on.

[BigKahuna]

Newmar appears to be. more up to date with the issue

https://www.irv2.com/forums/f103/mic...nt-582583.html