Welcome to 2CarPros.
Just wanted to jump in here. Make sure the LT tire will not rub under the fender. When you change from a 65 to a 75, the tire will be taller and narrower. As far as the LT, I agree with Alex. An LT has a heavier sidewall which is designed to carry more weight. It can be up to a 10 ply sidewall. On the other hand, a P rated tire (passenger tire) will have a 4 ply side wall. It isn't designed for as much weight. Also, the change in size may have an affect on how the vehicle handles.
Let me know if you have other questions.
Monday, April 15th, 2019 AT 8:16 PM