I'm maintaining an average of 18-20 mph but I pedal the entire time. I haven't pursued the 72V since my motor has fallen apart already at 36V. The axle separated from the case!! Luckily, Ken at It's Electric has been very prompt to replace the motor. Unfortunately even the replacement doesn't work properly. He suspected a defective controller, but that didn't fix it. It's going on 3 weeks now with no E-bike. I'm really bummed especially with the perfect weather forcast for this week and the steep gas prices. My commute is far too long to brave without the motor assist.