Tire Choice

Since they are 16's, I would definitely go with LR E

Replacing the problematic ST tires with a LT has always been a excellent upgrade for eliminating ST tire issues for all types of trailer owners.

Your ST235/80-16 E at 80 psi are rated at 3400-3500 lbs capacity.

However which LT depends on your trailer axles rating.

A LT235/85-16 E 80 psi at 3042 lbs capacity works great on 6k axles.

If your trailer has 7k axles then tires like the Goodyear G614 or Sailun S637 are popular sizes in the LT235/85-16 G load range at 3750 lbs capacity and 110 psi.

Some folks with 7k axles on their trailers have moved on up to the 17.5" LT tires and wheels.

6000 pound axles? Then any of the better quality LT tires will serve you very well.
7999 pound axles? Then your best option is to upgrade to 17.5 inch tires and wheels.
There are probably 100 pages on this subject just in the past six months. Use the search function above for hours of reading.

First, there is no LT235/80R16 - and this fact causes all sorts of discussion.

It is likely that you can replace your ST tires with a larger LT235/85R16, but you will need about an inch more clearance around the circumference.

Some folks have pointed out that an LT245/75R16 is closer in diameter to the ST 235/80R16, but they frequently forget to point out that it is wider by 5/8" when mounted on the same wheel - AND - it requires a minimum of a 6 1/2" wide wheel.

Then there is the issue of load carrying capacity. An ST235/80R216 Load Range E has a maximum load carrying capacity of 3420# at 80 psi, while an LT235/85R16 LRE is 3042 # at 80. (same for the LT245/75R16 LRE).

There is one school of thought that says you need to replace those ST's with something of the equivalent load carrying capacity - and that means a Load Range F (3415# at 95 psi) or a Load Range G (3750# at 110 psi.) - which are kind of hard to find.

With that approach, there might be an issue will the wheels - although some say that the load is what is important and the inflation pressure not so much - that if push came to shove, it would be preferable to use more inflation to get the load carrying capacity in the tire. In other words, which would be worse, not enough load carrying capacity in the tire or exceeding the inflation pressure limit of the wheel? In either case, there is a risk of failure - and it can be pointed out that we are aware that tires fail regularly, but we are unaware of any recurring wheel failures.


But there is another school of thought that says that an LT235/80R16 has a larger load carrying capacity because it is speed restricted to 65 mph - and that if you use an LT235/85R16 in its place(which is not only larger in diameter, which equals larger load carrying capacity, but also has a much higher speed rating), it is actually a step up in load carrying capacity.

You may find tire dealers who would refuse to mount an LT tire in place of an ST tire - a problem you can avoid by having the tires changed individually.

Now this topic is quite the source of discussion. I hope I have covered the issue without bias. The choice of how you want to look at this is up to you.

Replacing the problematic ST tires with a LT has always been a excellent upgrade for eliminating ST tire issues for all types of trailer owners.

Your ST235/80-16 E at 80 psi are rated at 3400-3500 lbs capacity.

However which LT depends on your trailer axles rating.

A LT235/85-16 E 80 psi at 3042 lbs capacity works great on 6k axles.

If your trailer has 7k axles then tires like the Goodyear G614 or Sailun S637 are popular sizes in the LT235/85-16 G load range at 3750 lbs capacity and 110 psi.

X2
for the Good Year "G" rated tires!!!!! My new Big Horn 5th. wheel had Tow Masters, I told the dealer "no Sale" unless they replaced them with the GY "G" rated tires. Job was done and I am a happy camper:)

OP's Cardinal has wheels that are only rated to 80 pounds inflation and have a history of cracking. So to install LRG tires would require the purchase of new wheels. At which point the best solution is to purchase 215/75R17.5 LRH tires and wheels. This tire is almost the exact diameter of of the Marathon's.

This is becoming one of the better choices for larger trailers and tire availability is wide from many 1st Tier tire companies. http://www.trailertiresandwheels.com/17.5x6.75-8-lug-series-03-hi-spec-aluminum-wheel
http://www.trailertiresandwheels.com/17.5-radial-tires

I believe the trailer has a GVWR of 16,095 and is 39'4" long. Don't skimp on tires for it!

If not already a member of the Cardinal Club, think about joining. http://www.cardinalrvclub.org/

Cardinal club member's wheel.

And yet another! This person had two rims crack!


Here is a link to the wheels in question:
http://www.tredittire.com/T03-P53.aspx

Chris

Michelin XPS ribs; assuming they are made in that size.

Dick_B wrote:
Michelin XPS ribs; assuming they are made in that size.

Great tire, however does come in a load rating for a trailer with a 16k plus GVWR.

Chris

How old are the China Marathons? The first try seems to have gotten a bad rep. They were just build to spec. The newest made in the past year should serve you better. New factory, on site GY employees to QC material and manufacturing.

I had to make the same choices. After much research and deciding not to change to 17.5 rim/tire due to cost I chose the Goodyear G614 and have been happy ever since. Just make sure you have a rim that will take 110psi as I did. American made tire readily available on line but pricier than the american branded but chinese/korean made tires.