Leni Riefenstahl remained both one of the world’s most influential film makers and (as she put it) ‘fascinated by the National Socialists’ up until her death as recently as 2003. ‘Olympia’ was perhaps her masterwork - it is certainly easier to watch than ‘Triumph of the Will’ (Triumph des Willens) or her other more overtly Nazi works.
The excellent cycling sequence in Olympia (which you can view on YouTube) features the 100km road race and includes action shots of both fork type derailleurs and pull-chain models. Unfortunately the shots are too brief and the resolution too low for even the anoraks amongst us to categorically identify them. Shame.
If you want to see the whole film there are DVDs commercially available - although they often seem to feature Korean subtitles.