Tires: Trailer tire towing speeds, steel rims, speed capability

Question
I'm considering purchasing my first trailer. Since it will now and then be used for a family vacation, I want to be able to travel at highway speed (for what I assume are obvious reasons!).

How do I know, in general, what the max speed is for a trailer tire? One trailer I'm looking at has these tire specifications:

   *  Painted 12 x 3.75 Steel Rims
   * 4-Bolt EasyLube Hubs
   * 4.8-12 (B) Tubeless Tires

How do I interpret that?

I really don't want to end up with something that I can't tow faster than 45 mph!

Answer
Tracy,

There is nothing about these specification that can tell you the maximum towing speed.  

But when I pull up the tire standard for this size, it says the loads listed are referenced against 62 mph - which means the speed capability of the tire is limited by how much load it is carrying - which means the trailer manufacturer will have to tell you if the trailer's speed is limited by the tires.