No blade of grass

if there were a freewheel, it would not click if the cranks were rolling forward regardless, even if they were turning due to rough ground or friction in the bearings or whatever. certainly not that fast anyway. just a thought.

It is fixed (or at least I suspect it is fixed).

The cranks move - and that is enough evidence for me to reasonably presume it is fixed.

The sound of the clicking freewheel is irrelevant, film sound is generally put on in post production, a field recorder would not likely pick up a noise like that - if you think what you hear in a film is what is on the screen then you may as well look for the invisible band playing the music that starts just before the bike shot.

Editor sees the rushes, sees the bike edit, sticks 'bike EFX' on his EDL/slate - the sound designer on the film (who shares the editors lack of interest/knowledge in bicycle drivechains) then gets a bicycle noise off an effects tape.

You are all idiots (except for Superprecise) and should be bitterly ashamed of yourselves.