What's your top speed?

i dont think it's possible to go faster then 40mph on a regular upright bike in the open air. too much resistence.

People who say they went faster are lying IMO or just have a faulty speedo.

For a while I became quite obsessed with how fast I could ride and how long my commute would take so.

Downhill, richmond park anticlock, fixed 67gi 35mph
Flat, fixed Herne Hill Velodrome, 92gi 38mph (cross wind not tail)
A4 (Talgarth road) My Hybrid commuter flat road drafing an hgv 41mph
Downhill hybrid again just after ditchling beacon toward Brighton 48mph

I agree with the wind resistance being a big barrier to fast speeds.