Mike,
As a test, and because I have been saying you can get replacement stuff for the Tailwind at Walmart, when I replaced the tires that we supply at 60,000 miles, I went to Walmart and got the cheapest tires they had. The trailer now has 78,000 so there are 18,000 on the cheap Walmart tires and they look very good still.
It is starting to look like the tread life is much better at higher pressure, but the ride on gravel and other unimproved roads is worse. I pulled my Escapade with the my 1500 which was always ridden more easily. I run 30 to 31 in all the 4.80-12 tires, myself.
The Tailwind has been on the back of the 04 1800 since new and has been pulled through the turns at much higher side loading, and a lot higher cruise speeds. The Escapade has probably never been in triple digits and the Tailwind is there all the time, not that I condone that type of operation. If there is a problem, I want to be the first to know it. The very first time the Tailwind was pulled, it saw 118. I would expect the Tailwind tires to go 75,000 if the speed limit was always obeyed. My own Tailwind first tires would not have made 75,000, but would have gone 65,000. Those tires spent a lot of time above 80 (now the speed limit in west Texas).
Try Carlisle Sport Trac tires and see how you do on mileage. I bought two of one manufacturers trailers (not Hannigan) that had suspension problems on both and the tires wore out to the cord in less than 8,000 miles on both. Therefore, the suspension has a lot to do with tire life. After I modified the second of these Trailer's suspension, I got 50,000 miles on the same kind of tires.