I do not set a specific speed limit - adjust to time of day, traffic, highway conditions,terrain, many factors, if i feel unsafe at 55 I do not drive it. i have pulled my 35 foot 5th with slide out at 70 and felt- comfortable.However i would not and do not,do so in baja. Your specific situation, determines your speed.I have towed 28 foot TT when 60 - 65 was plenty fast.