I'm not sure why there is so much "OMG NO YOU CANT GO THAT FAST THAT'S IMPOSSIBLE" type of responses on here. To be clear, I'm talking about achieved top speeds, peaks - not sustained speeds.
Bicycles without a motor can be ridden long distances on a flat surface at 30 mph. That's normal for a properly geared, professional road bike with a trained rider.
Without a motor, people draft cars or go downhill and get up to like 100 mph.
The limits of how fast a MB can go is often related to the bicycle mechanics itself, not the engine.