Normal max speed is around 32mph on the long downhill leaving work. All time max speed was 35mph on a flat section of road drafting a line of cars with a tailwind. Not bad for spinning a 42/11 on my MTB. I lasted less than half a mile at that speed. If you count going to my parents'/sister's houses as commuting, then my max is 47mph down an 18% grade with a Camelbak on for extra aero effect (no exagerration factor added)