Tire selection help

The sticker weight ratings aren't as important as an actual scale weight. For my trailer, the GAWR is 3320lbs, GCWR is 3500lbs; fully loaded scale weight is 2400lbs.
When I had the radials on my trailer, the tires were way under the GAWR/GCWR numbers but barely OK based on the scale weight (I had about 200lbs headroom). In this case, the tires were the limiting factor. My new bias tires exceed the GAWR/GCWR so the axle & suspension are my limiting factor.

If you're concerned, go get it weighted at a truck scale and use that number instead of the sticker numbers. Best is to scale when loaded for the longest trip expected with full water, propane, food, etc.

Thank you for your help. I went back and checked my pictures that I took and they are D13 that are currently on the trailer not R13. What i still find troubling is that even the load range D tires in the current size will barely meet the GAWR of the trailer (about 50lbs above the rating) but is about 500 lbs short of the GCWR. I have to wonder if this is why the outer edges of the tires are wore down to nothing while the centers are still good. I know that they aren't under inflated because I just checked them and they are still at 65 lbs.
It really shouldn't be my concern since it isn't my trailer, however since I have offered to tow it to him (about 200 miles) I want my family to be safe when doing this. Maybe I am just over thinking it.

Check the manufacturer's label; I bet that the tire size will be ST185/80D13 indicating a BIAS tire. The tires presently on the brother's trailer are RADIAL (R13 instead of D13).
I had the same problem. When I purchased my "experienced" trailer, the dealer put brand new radial tires on it. When it came time to replace them, I couldn't find a D load range radial. I just put a set of Carlisle Sport Trail from Discount Tire. It cost me about $200 installed with road hazard warranty! I put 700 miles on them this weekend and I had no issues. They bounced a bit for the first 50 miles but then were smooth and solid. I made sure to have 65PSI in them.

Since bias tires are stiffer than radial, they react more to the road surface. Most notable was occasional wiggle from the ruts in the pavement, but not enough to be a problem.

For those who poo-poo Carlisle, the old tires were the Carlisle Radial Trail, lasted for 6 years, had half of the original tread left, and had almost 20,000 miles on them! I average 3,000 a year on the trailer; one of those years had over 5,000 miles in a single trip. So I felt that I had good life out of them. They were replaced because of age and one tire started to show damage in the sidewall and tread area.

I found D load range 13inchers at etrailer.com last year tires with wheels for about $100 each. I bought two and got free shipping. Hope this helps - Dave

Kendra Karrier is one of the few LR D 13" tires on the market. We had 14" LR D's on our last trailer that gave good service. I know eTrailer has them, but you might be able to get them locally also.

Karrier LR D