Wind resistance will be more of a factor than the well lubricated swiss made gear box.

+ there is the hub , 3 speed ... overdrive is 4/3 of the 2nd gear...

a Moulton or another with a ZZipper fairing in front.. will get you a bit more speed , not laying back, low, on a Recumbent speeds ,

but the fairing smooths the air flow better than just your body..

To go really fast the bikes have a counter shaft ... and a second BB, a small cog on one end big chainring on the other , and a second chain driving the wheel hub

raising the gear to huge sizes, but they use a Motor Pacer blocking the wind and get towed to 60 Mph, before pedaling to the speeds of around 150 mph..

Bonneville salt flats speeds..