right, i’m back.
re biopace not being completely wrong:
riding along at a constant speed means that the chain will be moving at a constant speed. Using round rings means that your feet will also move around their circles at a constant speed. The idea of biopace is that moving your feet at a constant speed is actually a bit tricky (especially at the top and bottom), and the alignment of the biopace oval means you can keep a constant chain-speed, with naturally varying foot-speed.
like i said, it’s sort of interesting, in a geeky way, but the obvious outcome of biopace was that it made pedalling harder when your legs were at their weakest (at the top of the stroke, when your knees are most bent).
You could possibly say that biopace might suit a time-trialler, hoping to maintain a constant speed. and the ‘traditional’ oval rings we’re seeing again might suit a mountainbiker, whose speed up a tricky hill definitely isn’t constant…
maybe…
i suspect there is at least one phd-in-waiting on the aerodynamic benefits of biopace, as a reduction in foot-speed would mean a reduction in drag…