I would not comment on the thoughts that get expressed in the cab of my truck any time of these rigs blow by me while I am doing 60 - 65 mph.
Flying down the road pulling any size of trailer has a direct impact on safety not only to the person driving in that way but to others on the road, and I hope to not be on the same road or any distance behind when these people are choosing to exercise this "right".
EDIT - I was in the middle of editing my post when the browser crashed.
I wanted to add a response to the OP's question and had a bunch of stuff typed up but now it is gone. I was basically saying that - sure, if the tires and rims are uprated and you have taken approriate anti-sway measues you will be able to go faster.
Many jurisdictions limit speed to towed vehicles -
here is a PDF that shows limits by state. That ST tires have a 65 mph limit is therefore not surprising.
