op says wrote:
Unless I am mistaken, LT tires need a little wiggle room on the weight rating. Is the weight rating on this tire sufficient for my 8500ish axle weight?
We have always ran our LT tires up to its max load capacity since the beginning (many many years before the net).
Example is the LT with 3042 lbs capacity on a trailers 6k axles are the main stay for commercial haulers running the interstates.
And the 3/4 ton truck has came with 6k rear axles since the '70s with a LT E at 3042 lbs capacity.
Your trailer with 8400 lbs on the axles = a 2100 lb capacity tire as a minimum. The 15" LT we have recommended would have have around a 15 percent reserve. Looks like a good match.