That's mph, not kph. Calibrated by an average of 3 measured rollouts with my full weight on the bike. Doesn't get much more accurate.

54.6mph reached during the Summits of Bothell ride on a 1/2 mile straight downhill stretch with a clean runout at the bottom. I might have been able to go faster, but I chickened out and started tapping the brakes before I reached the bottom. Course record on that hill is supposedly 57mph.