Michelin 235/75R15 vs. 225/75R15, size issue?

[chrispe]

Hi everyone,


being new to the Airstream world (soon; waiting to take possession on a '21 GT 27FB ) and following some general recommendations I wanted to swap the tires right on delivery for a Michelin Defender.
Now realizing that those only come in a width of 235 and not 225. Is that an issue with overall clearance in the wheel housing maybe having those additional 10mm?
Also, would there still be anough space for Centramatics (in case we would decide to go for them)?


Thanks a lot,
Christian


PS: Tried the search function but wasn't successful...

[Hans627]

Congrats on your new AS. I hope you get it soon. And make sure you post pictures.

Michelin makes great tires, no doubt. But the AS's have Goodyear Endurance tires that are getting great reviews. You might want to read up on them and read some threads on the forum about GYE tires.

There will be a lot of things you want to get for your GT. IMHO tires are not at the top of the top of the list.

All the best!

[SeaLevel]

Originally Posted by Hans627

There will be a lot of things you want to get for your GT. IMHO tires are not at the top of the top of the list.

All the best!

I agree. You can probably get 3-4 years out of the GYE tires. Getting a TPMS system for them might be worthwhile, but there's no need to swap the tires out right away.

[BayouBiker]

The stock clearance is about an inch so you'd remove about half of that, it's getting close. But why ditch the stock tires? The Goodyear Endurance are an excellent choice for an Airstream. They are designed for trailers and they are the correct width for the rims. The 235's are too wide and compromise sidewall geometry. Michelin specifically disclaims their truck (LT) tires for trailer service and the load index of 109 is quite a bit lower than the Endurance 117. You need the high load range to resist inter-ply sheer which is a problem for multi axle trailers. Your proposed tire swap is a significant technical downgrade. I recommend caution before proceeding.

[chrispe]

Hi all three of you,


to be honest, it is as usual with doing lots of research, there are so many opinions out there
Reading so much about is sounds everywhere, that the Michelin Defender LTX is the "non-plus-ultra" and as I want to get rid of the spare tire (tow hitch weight reduction - different topic!), I though it would be a good idea to be safe.
Makes all decisions really hard


Cheers
Chris

[Hans627]

Originally Posted by chrispe

Hi all three of you,


to be honest, it is as usual with doing lots of research, there are so many opinions out there
Reading so much about is sounds everywhere, that the Michelin Defender LTX is the "non-plus-ultra" and as I want to get rid of the spare tire (tow hitch weight reduction - different topic!), I though it would be a good idea to be safe.
Makes all decisions really hard


Cheers
Chris

Keep the GYE tires and get a TPMS. Plus a portable air compressor. Just trying to be helpful. But, of course, it is your decision.

[chrispe]

Hi Hans,


always appreciated, absolutely!


Thank you

[Bill M.]

I run the Michelin 15" tires. On my 3rd set. I like them and the way the trailer rides with them. But...I put them on when Goodyear only offered the Marathons. Marathons were terrible tires. Apparantly all of the problems with the Marathons have been corrected with the new Endurance tires. So even though I run the Michelins i think you will be as well served with the Endurance and re-think in 3 years. I do not think there is a safety problem with those tires. If it is a 2 axle trailer you do not really need a spare, at least in most places.

[chrispe]

Thanks Bill!


That's where it get a bit confusing to me, I read a lot about the Goodyear Marathon issues, but then many also recommend still changing over to the Defenders even from the Endurance ones.
I am just looking for a proper, safe and "no worry" solution, so also want to avoid flats, etc.


Thinking about this now already as the dealer offered to change them over for free as part of the PDI.


Cheers,
Chris

[BayouBiker]

The Endurance really are excellent tires for trailers. They are still fairly new on the market but reported experience has been top notch as far as tires go. I have not seen any reports of defect related failures and I searched the internet quite thoroughly for it. My experience has be excellent as well. 11,000 now and they are looking very healthy. Spin tested them last week and they are perfect. Wearing evenly too. Give them a chance you won't likely be disappointed. Airstream recommends 80psi max pressure and they will be most reliable at max, but a bit harsh on the trailer. I run mine at 25%-30% above required load capacity so 62 psi for my 25' and stuff in the trailer no longer ends up on the floor or damaged.

[PKI]

We have the Michelins installed on our 23. They are the 235s and fit quite well. Also have the Centramatics installed. However, that does not help you. All trailers are a bit different. The bigger trailer you have will be heavier. The threads on the switch from the ST to the P tires identify that the P has barely enough weight capacity for a 27. Suggest you run the numbers yourself.

I really like the Michelins, but in all likelihood, moving to 16's would be a better approach. Not given to that concept, running the GYEs may be the best solution. It's certainly not a bad idea.

IMHO, the "run with no spare" is a bad idea. It removes the important option of putting the damaged tire in the rack and running the spare. Running on one tire for a short period is doable, but it will somewhat compromise the tire that is run single. Personally, I would never trust a run single tire. The cost for repairing blowout damage is way more than the cost to replace a tire. Caution certainly advised.

Note - I really do like the Michelins - a lot. I would install them on the 23 when this set needs to be replaced. Note - I really think the GYE is a quality tire and I believe it would be an acceptable alternative to the Michelin. IMHO changing from 15in GYE to 15in Michelin would be counter productive on a 27. However, if you felt inclined to upgrade to 16in wheels, the Michelins would make an excellent tire for that application.

Hope to meet you down the road with a smile. Pat

Edit - Michelins do not avoid flats. We had one in the first year we installed the Michelins. The potential to have a belt separation is much less with a Michelin or a GYE. It was the GYM that had this problem. However, a lot of GYMs rolled a lot of miles with no failure. Ours were China built and ran 20K miles before we pulled them. They sit in a hot shed and have been there for four years. No explosions yet.

[ROBERT CROSS]

Running without a spare is a bad idea...running a tire not made for trailering can also be problematic.

We have 15k on our GYE's without a problem.👍

Bob
🇺🇸

[chrispe]

Thanks everyone!
This is really good feedback again
I feel like giving the GYE a try makes sense and saves also 600.- USD for now...maybe better invested in the Centramatics at this point.

@BayouBiker: so airstream recommends that much over max load recommendation in terms of pressure, did I get that right if you say 60-65psi is already 25% over the GYE load recommendation?

[BayouBiker]

They do. Using my trailer as an example. The GVWR is 7300. With two full water tanks, my actual weight is 7250 lb, and I have 6140 on the axles, this is from the truck scale 2 weeks ago. Divided by four assuming the weight is evenly distributed that is 1535 each tire. Allowing for 10% variation that is 1688. Now from the Goodyear load chart The minimum tire pressure required to carry my actual trailer load is 33psi. Looking at the Airstream sticker, they recommend max pressure or 80 psi in all tires. taking the 1688 and adding 30% more capacity that is 2195 and going back to the chart, That is about 55psi.

So I started out for the Smokies a couple weeks ago at 55psi (30% over). On the road, tire flex warmed them and pressure rose 6-7 degrees which corresponds to about 60-65 degrees which is above the 20-50 ideal. So I raised the pressure to 60-62 psi and the new increase was less than 5 psi, corresponding to about 40 degrees which is in range. So I guess I am actually about 45% over minimum required.

I ran them at 80 psi for the first 2000 miles but they were so jarring to the trailer content I was breaking stuff so I backed off. Note that catastrophic tire failure occurs most often from either or both excessive heat and sheer stress so running the tires at maximum design pressure will reduce the risk of tire failure since both of these issues are minimized at max pressure so there is a trade off here.

[jcanavera]

The Goodyear Endurance is relatively a new tire and initial reports have been good so far. Back when my Classic was regularly losing ST tires with belt slippage I was at a decision point of changing out my ST's every three years or going with a better tire. I made the decision that going with 16" wheels and Michelin 225x75R 16 tires was a good move and made better economic sense. My trailer was at the time the heaviest trailer that Airstream built on a tandem axle and I think the ST's I used (Marathon's and Maxxis E rated) were just not up to the task after they reached 3-4 season of use. I just replaced my Michelin's last year after 6 seasons of use. I moved to the Defender series at that time and that tire has been superseded with the Agilis model.

New build Airstreams can be upgraded to the Michelin Agilis tires but you have to go with the 16 inch wheels. Not knowing what trailer you bought, but with the good reports so far with the Endurance tires, you may find that they are perfectly acceptable. Even though the LT Defender tire is available in the 235 size, It is for a 16" wheel and the tolerances to me are a little too close to feel comfortable with.

If I were in your shoes at this point I might hold off keep the 15 inch wheels and go with the Endurance tires. If you just don't want the Goodyear product then it's 16 wheels and using the Agilis model since we all know the fit is good. I think if the 235 size Defender was a reasonable option, Airstream would have offered them since the Defenders are a little less cost than the Agilis.

Jack

[Doc Foster]

I got 45,000 miles on my Endurance tires on 30' International over 3 years. Probably could have got another year out of them, but plan on putting at least 10,000 miles on the trailer this summer, so went ahead and put on a new set of GY Endurance tires for peace of mind. They are far superior to the old GYM tires, plus they are ST tires, but that is a whole other debate.