I have ~3.5 yr old GY Marathons on the boat and just got back from the trip to the Keys. 3 of the 4 failed, tread separated. Tire pressure was always checked before every use and the tires are in the shade most of the time. Back in the day I went with GY because most people really liked them. I talked to the trailer builder (Owens&Sons) and he said he switched to Towmasters radials about 2.5 yrs ago because he was seeing tons of GY fail in exact same manner. He is 2nd generation trailer manufacturer so builds and sells alot of trailers and he said it was a trend. Although with blocks of wood and all my recent practice I can change one out on the side of the Interstate pretty fast, I am growing tired of the event. Thankfully, I pulled over and checked the remaining 2 right and found one separating right before the 7 mile bridge connecting Big Pine Key , that would have been festive. Just curious if anyone else has seen increased failures and if anyone has option of what tire to try next, trailer is small (20ft boat) so I am stuck with 14" options, in fact can't fit a 215 under fenders , so stuck with 205/75/14s. (load range C obviously)

Goodyear dealer just replaced four 215/75/14's for me with same issue you have. Mine were 5 years old with about 15000 miles but stored inside when not boating. Goodyear was good about it, cost me $26.00 per tire for new replacements.

Carlisle (steel belt)is having the same issues as recently as 3 months ago. I bought a set (6) in Dec. 06 and they had about 3000 miles on them, stored mostly indoors. In May I smoked 5 of 6 in a 200 mile pull. Two shredded, the rest separated badly. Carlisle asked for the tires back, then replaced the whole set for free/ they paid my dealer for mount/balance/install. Total cost to me $0 but I got pretty good at roadside changes. Came home with 5 tires on the ground/ happened to bring 2 spares but I had to buy another along the way.

New set has been fine so far/ have about 1000 miles on them now.

IMO all 14" trailer tires are a crap shoot. I was lucky enough to have enough clearance to be able to change to 15" wheels and tires. The only thing I would do different is buy Maxxis tires instead of Goodyear's. The people that have 16" tires are the ones that have less problems because of the wider selection in tires. I think Goodyear has the best warranty, as they will pay for any trailer damage as well as for your tires. I think all Marathans are now made in China. Knowledgable people say that after 3 years replace your trailer tires no matter how much use they have had to prevent possible problems. My advise--buy 2 spares and a good jack, do good preventative maintance and drive under 65.
Jay

I don't have room for 15"s, don't even have the room for 215 profile 14" ones. So tomorrow I pick up 4 new 205/75/14 ones, my trailer dealer said he has had decent luck with a brand I never heard of , Transmaster, (somewhat troubling). Guess I will try those, who knows, I have sorta lost confidence in trailer tires.

Because I trailer every place we good I wanted to stay with a brand that I knew we would be able to get most everywhere. And the warranty means a lot also. While I still believe Marathons are crappy they really aren't much worse than the other selections you have in 14" trailer tires. Some people have good luck with different brands--it's just a matter of opinion and which brand you have had the least trouble with.
Jay

Interesting. My 15" GY Marathons are 4 seasons old and have @ 5,000 miles on them. Trailer is stored inside when not in use. I usually go 5 seasons on a set of tires. Might consider swapping these out next spring just to be safe.