I had longer schackels made for the rear of the leaf spring , just bolted them on, cost 20.00 , Now use a 225 14 load range d and improved clearence of the tire to the trailer.
If you get too big of tire the tire will rub the boat hual on the trailer if boat is not tied down in the back. The tire is so wide it extends out further than the fender on the inside.
I pull the boat 715 miles round trip on the roughest roads in the country,
(Alaska) and this has worked well, I suggest bying the best tires money can buy for a single axle trailer, mine were 105.00 each.
I now leave the boat in the water for the summer and only have one trip ayear vs 5 or 6 in past years. After a 5 1/2 year wait on the waiting list for a boat slip in Valdez Small Boat Harbor. at a cost of 571.00 for a year, now you know why the wait is so long.