Tires for my fifth wheel.

1) What size tire do you have on your Montana?
2) I would be willing to bet that you are running way under inflated at 75 psi.
You will receive numerous suggestions on installing LT trailer tires vs ST trailer tires. Your marathons are ST trailer tires.
I run Maxxis M8008 ST 16" tires on my fiver. I really like them and I could afford them. Maxxis is the ONLY ST tire to run. Two popular LT trailer tires are Michelin XPS Ribs and Goodyear G614 trailer tires.
Stay away from any ST tire made in China as they don't have a great track record. As mentioned, Maxxis is the ONLY ST trailer tire to consider if you choose to go with ST tires.
Run the ST tires at Maximum pressure. Be sure to have them balanced, too.

It appears that all Montana Mountaineer's used 235/80R16E tires and they need to be set at 80 PSI cold. I don't know if 5 lbs too low will cause all the problems you had since other variables come in to play as well such as your traveling speed, how heavy you were and what the ambient temperature was. But the biggest contributor was simply you were running ST tires. They are just flat unreliable when used on the heavier 5th wheels. We changed from the OEM Chinese made 16" ST Tires on out Montana 3400RL to 16" Bridgestone R250 Duravis LT tires and have not had trouble since. They will run around $200 each. I believe the Maxxis ST Tiresare quite a bit more expensive. I will never install another ST tire on a 5th wheel or trailer.

Did you keep the old tires? I've always heard the Goodyear is very good about covering the tires and any damage done. Be worth checking with a dealer. I also agree with amxpress; you may have been under inflated. Highway driving, heat generation, low pressure. Not a good combination. Sorry for your troubles, and good luck.

Well we have Bridgestone Duravis R250 LTs under our Mountaineer. Time will tell, but so far I like.

I have my ST pop corn popper plugged in and warming up. Got a glass of wine poured and am ready for another round of you were underinflated, curbed your tires and/or did not maintain them correctly. And should continue to buy more cheap ST tires. Chris

I run Michelin LT truck tires on my 5th wheels. Currently have XPS Ribs. I prefer not to have blow outs so I stay away from the Chinese junk.

Me Again wrote:
I have my ST pop corn popper plugged in and warming up. Got a glass of wine poured and am ready for another round of you were underinflated, curbed your tires and/or did not maintain them correctly. And should continue to buy more cheap ST tires. Chris

Ummm...so far, you're the only one to go there. Just sayin'

OK sorry Maxxis is a more expensive ST and not without problems of early dry rot and thrown caps. One must be sure they came from Thailand, as Maxxis had many plants in many countries. Chris

I got rid of the marathon tire a year after I bought my camper, maxxis 880 for me.

Lots and lots of threads online on the topic....always comes down to a few top rated tires as options and a few other scattered favorites. Heres the top ones in every thread.

Maxxis ST
Michelin XPS Ribs LT
Bridgestone Duravis R250 LT

There is often mention of the newer Carlisle ST tires as being very good but Carlisle has a long reputation of lousy ST tires over the years that will be difficult to reverse. The Marathons used to be a good tire but much talk on these forums of blowouts lately.

I myself have the XPS ribs and so far so good. Have been a solid Michelin fan for decades. However, I recently had a blowout on my truck with Michelin LTX M/S2's. Set of tires were only 3 years old and 30,000 miles. All 4 had cracked sidewalls and dry rotting on tread. Bad batches sometimes even on top rated tires.