i was looking to see where a set of 12 inch wide sport car tires were made yesterday, they were at a friends shop and was surprised to see Russia and they were premium tires

+1 for Goodyear endurance, I replaced some 6 year old China made marathons, I loved that they were made in the USA. I also have a sharp entry to my garage and they work great and track well, take care of them and they will be good to you, I replace every 5-6 years, and my tires are only in the sun when the boat is off the trailer for the day, and never parked on moist ground

I'm diggin that 19.5... it matches close to the ones on my truck

Nothing will beat switching to 17.5" commercial wheels. Tires are 18 ply and rated for 6,005 lbs each.

I have 16" Firestone Transforce HT on my 38 Myco and love them. So nice to have real tires on the trailer. I'm light for a 38' so these are more than sufficient

No more E rated for me as the front and rear on my right hand side (triple axle) tear up way too fast due to tight turn into my driveway. Load G's are handling it without fuss thus far.

The MYCO trailer under my 38 EC has 6 Hercules H-901 All Steel LT235/85R16 tires.
I trailered back and forth to the ramp every weekend and in May the boat came from TX to MD. No issues whatsoever but they aren't cheap.

I have a triple 6k torsion axle steel Manning trailer to haul my Sonic, 12k lbs total boat and trailer combined with full fuel. I got 2 years out of the china ST 235/80-16 E rated tires before one of the fronts blew on the freeway at 75mph when going over a overpass (bump) in the road. Replaced 7 tires with Michelin LTX 245/75-16 in July 2011. Boat and trailer constantly stored in climate controlled garage (60-65 degrees and 55% humidity) year around except when using a few weeks a years, so maybe out side a total of 3-4 weeks/year. Trailer and truck is parked in garage on horse stall mats (3/4 inch thick rubber) for July and August during our Michigan boating season and elevated on Jack stands the other 10 months of the year. Rotate tires every winter in a X pattern just like a truck but 1 extra axle. Towed approximately 30k miles over last 10 years at highway speeds of 75-85 mph without any issues and yes there is considerable sidewall flex especially when backing into the garage.

Late last Sunday evening (most towing done thru the night) I had one center tire blow then an hour later at 75mph on the freeway the opposite middle tire de-tread itself, both on perfectly smooth highways. Fortunately I had an extra spare in the back of the truck with the original china ST tire to make it home at significantly reduced speed since I had no more spares in the middle of the night. So diligently performing every tire maintenance detail that I was aware of, the tires still failed almost exactly at the 11 years mark with ~60% tread remaining.

I think the LT tires pulled harder at their max of 80 psi vs the china ST tire at 90 psi, however I felt confident when I hit 90+ mph on downhills the tires would handle the speed and always thought the boat was getting a Soft ride.

Now I need 8 new tires, considering the Goodyear Endurance ST 235/80-16 E rated tire as this is a new tire since my last purchase and made in USA, so I would expect a better quality than ST tires a dozen years ago. However I'm really concerned with the speed rating on "N" 87 mph and will the tire hold up to 5+ continuous hours of 80-85 mph (yes that's why I tow during the night when there is empty freeways).
Or, should I stick with the LT E-rated truck tires for the higher speed rating?
Or, a G-rated commercial tire like the Goodyear G614, but for more than double the price I think they would still have deterioration before 10 years just like the LT tires, so not sure that route would offer any extra value being it's only 12k lbs.

Thought I would share my experience and hopefully get some thoughts. Thanks in advance.

7 years is the max I would ever expect or run ANY tire. Go with the LTs again if it worked for you.

I have Goodyear Endurance, E-rated, in a 15" size on my toy hauler (all that will fit), and they have been great tires. And that toy hauler is not babied. It's always loaded to the max, torqued around gas stations, all highway speeds, and the like.
I am selling this TH, as I upgraded and will need to figure out a 16" setup for my new one.
I like the concept of G or H rated tires, but they are usually twice the weight. You have to think about how that abuses your suspension, axles, brakes, (affects stopping distances too), and bearings.

Purchased 8 new Cooper Discoverer HT3 LT245/75R16 E-load. The Michelin LTX I had previously is no longer available and the newer LTX tires are more of a all-season tread. The HT3 are more dedicated highway/commercial tread design. I plan to follow my same tire maintenance regiment as stated above but will remember to replace at the 7 year mark. What I failed to notice, the previous LTX tread barely fit inside the fender lip, especially the front axle at the launch ramp. The new HT3's tread is .4 inches wider and I had to slightly flare my fenders by roughly 1/4". Thanks to all in this thread for the advisement's.