225/75r15 down to a 205/75r15

Thanks for the info I stayed with the 225

I was considering dropping one size from a 225/75r15 to a 205/75r15

Actually that is 2 sizes. There is a 215/75R15 but it is not very common. I also agree with the others. Stay with the 225's as it will affect your capacity.

I would not recommend your suggested change. It will affect the GVWR of your trailer and may be unsafe. Even though both are Load Range "D", the larger tire has more max load capacity.

I captured the following info from Tirerack.com regarding one of their ST tires*:

P205/75R15 - Max Load 2150 Pounds
P225/75R15 - Max Load 2540 Pounds

You would lose 390 pounds of capacity per tire. That is 780 per axle, and 1,560 pounds on a tandem axle trailer.

* Power King Towmax STR.

I went from 205 C's to 225 75 15 E's. No tire problems for the 7 years I ran them. I don't see a 1/2" lower as a benefit.