Most ST trailer tires are speed-limited to 65 mph in their ratings. Depending on how close you are to the load rating on the tire you may be asking for a blowout.
I typically tow between 65-70 as that's the sweet spot for my drivetrain. I feel like 75 is pushing it for my rig, but if you have the hitch set up right and the rig is well balanced you maybe OK.
Also be aware that fuel consumption increases exponentially with speed because of the huge wind drag created by the trailer. No exaggeration, it may cost you a few hundred $$ over your trip more to cruise at 75 vs 65.
Not saying don't do it, just be aware of the implications.
