I have a small 40" x 48" Harbor Freight trailer with 12" wheels, that I used to tow behind my car to carry about 450 pounds of race tires and pit gear. It has about 30K miles on it, being towed at the prevailing speed limits which in some states is 75 MPH. I went across a certain alley in south Florida so fast that the license plate bent up 90 degrees from the air drag, and the trailer followed along nice and smooth the same as if I were driving 30 MPH in town.
For legal reasons, I don't recommend exceeding the manufacturer's maximum recommended speed. However, if your foot accidentally slips on the throttle,

the small HF trailer kit seems to be stable for extended runs at 75+ when loaded at half its rated capacity and balanced properly.....