Top speed. On another review page someone mentioned they had taken it to 93 mph...a medium sized person. I´m a big guy at 6´4" and have had mine at 75 and had tons of throttle and rpm´s left so I think it would easily do in the 80´s. I get buffeted too much with wind above 65 for my tastes so usually find a groove around 60-65 and roll along there with good mileage too!