I spent the money on the best 4 on the ground .
That means an LT tire not an ST .
in the 15 inch the clear choice is the Goodyear G26 Cargo in a size
225/70R15c LOAD RANGE D .
placarded for 2450 # on an LT scale .
Do a search for the data by placing G26 I the search box above .
In 16 inch tires there are many choices .
The highest weight rating posted on the sidewall is more important than the brand .
The Bridgestone Duravis ( R250 and R500 ) are heavier than the cheaper Bridgestones and many of the name brands .
If you have room for LT265/75R16 load range E you can get 3415 # rating and the choices are myriad .
My spare has never seen the ground .
I removed the spare from my boat trailer after switching to the Kumho 857 size 205R14 , rated 2271 # on the LT scale .
I upgraded about 45 % with that change .
By adding another 25 % - 45 % of load rating I have reduced my tire issues to zero for my TT and my boat trailer ..