I've been running "E" range truck tires for many years with no problems. Ask your dealer about "take offs" and you can save almost a third of their cost. You're wise to be weary about the tires' age issue. It has been discussed at length in this forum, and it's been determined that old tires can be a real threat to your safety.

Gard

The 14 ply tires  "G" Rated will require special rims rated for 110 psi.  Most tire dealers will not install the "G" rated tires on your stock rims.  So if you want to purchase the 14 ply tires, plan on upgrading your rims at the same time.

A 235/85/16R tire is rated at 3400 lbs at 80 psi.  Two tires at 3400 lbs each = 6800 lbs and is more than adequet for your 6000lb axles.

I see you are in San Antonio and I would hope any reputable tire dealer in a city of that size could order in trailer tires in that size. That is a very common trailer tire size and rating.  If you put truck tires on use tires with a a Hiway Tread.  They will track straighter than "AT" type if tire.

Take offs are new tires that are sold off of newly delivered trucks, by owners that want other than stock, factory tires. The tire dealers take them in trade and resell them at discounts. I would not recommend any off brands, particularly the Chinese variants. Stick to the top of the line, name brands.

Gard

Remember... These "ST", special trailer tires are rated for a maximum speed of 65 mph.

Since you're traveling in areas where the temps can go extremely high, I'm sure you will take that into consideration in your tire purchase.  Keeping them properly inflated will help a good deal.

I once had to replace my tires a pair at a time. But I was able to match them up to what was on there. Tread, size, type, etc.

Michellin is a good choice for a trailer tire, especially in high heat conditions on the road surface in Texas.  Michellin uses a very hard rubber compound, hince the "wear like iron" reputation in the tire industry.  My nieghbor has a Ford 4x4 a little newer than mine and it's a daily driver for him.  He's an account manager (salesman) for the local CAT dealer. He likes Perilli Scorpions because they handle so well.  Problem; he puts a new set on every year at about $800.00 annually.  He drives hard, puts at least 45k miles on each year and doesn't complain too much until he finds out I'm only on my second set of tires with my 2001 super duty 4x4.  Perilli is a soft compound tire, gives great handling, stick like glue and ride smooth.  Don't expect all of that from a Michellin heavy wall tire.  They will give excellent service, last a long time and will probably suffer from sidewall cracking from UV damage before the tread wears out.  Just my humble opinion.

deranger

Since we are talking about tires I have a couple questions. The other day I noticed a HUGE bubble in one of our trailer tires, just as we loaded the horses. Needless to say we UNLOADED and changed tires before we left. We had just come home from a trip too the day before.

My question is what causes tires to get bubbles? I also noticed small cracks in the side walls of a couple of the other tires. Nothing longer than an inch, but don't know what caused those either. We don't do much gravel road traveling. What kind of problems could those cracks cause later on?? should we replace them now?

I couldn't tell you what kind of tires is on the trailer but I do know they are 10 ply and was told they are 18 wheeler truck tires, if that tells you anything LOL

Bubbles or blistering can be caused by either the delamination of the cord or the cap to cord bond. As a tire heats up, the heat in the sidewall and bead areas, increase at a faster rate than the center of the tire. The construction of a tire is much thicker in the bead areas, and the heat cannot dissipate as fast as the thinner more flexible parts of the tire.

The increased heat can cause the cord to delaminate, which causes stress fractures to appear in the sidewalls. The cap is bonded to the cord. If there is a partial failure of this bond, caused by excessive heat or an impact fracture, a blister can result. If the cord breaks a belt, it usually shows up in the sidewall as a wavy profile, but it also can appear as a bubble or even a fracture in the external cap rubber.

Generally speaking, the bubbling is the result of the tire overheating, or being subjected to an unusual impact; pot holes, rocks, dropping off the edge of the pavement etc. Maintain your tire pressures, don't overload the vehicle and be careful of running older tires.

Keep up your vigilance, you did well to recognize a problem, and alleviate it before a blow out occurred.

Gard