I see that the thread thinks these tires are for a trailer. I don't think it matters as long as the trailer tows level.
However, I have to take exception to @Grandpere's recommendation to put the new ones on the front. The reason is this: presumably the old tires will wear out before the new ones, when that happens, you will have infinitely better traction on wet roads on the front axle, and this is a prescription for disaster. When considering future events, you must think in terms of probability, what is likely to happen vs what is theoretically possible. Your odds of a blowout are extremely tiny, but your odds of hitting a puddle are all but certain. Think about it, in your entire driving life, exactly how many blowouts have you had? Can you even guesstimate how many puddles you've hit?
If you hit that puddle with good tires on the front, and worn out or bald tires on the back, you are going to go for a ride through the weeds, mostly sideways, but a little backwards. Your crash protection is designed to be most robust if you are going forward and hit that tree, but if you are sideways, you have almost nothing. If you have an axle sliding because of that puddle, you want it to be the front axle, not the rear. If you are going to hit anything, you want to take the blow on the front of the car, not the side.
Reputable tire dealers know this too. The NHTSA recommends new tires always go on the back, NEVER the front for this reason. A reputable dealer should refuse to put them on the front, as he risks getting sued should you take that ride sideways through the boonies.
