backdoor wrote:[https://www.youtube.com/watch?v=-9gQ1KRhesM&feature=youtu.be
-------------
The Ceramic Speed 'variable pinion' drive train that you mentioned is quite interesting. But I think the major trouble spot is dirt contamination of the exposed rolled bearings. This is basically a 'mechanical engineering' problem regarding how bearings work in adverse environments.
In addition to watching that specific youtube, I also watched several others that discussed oval chainrings.
Regarding your (Noel / Backdoor) theory about applying high torque during the 11-1 o'clock portion of crank rotation, It occured to me that an OVAL chainring that was oriented so that the high-tooth portion occured DURING that 11-1 o'clock position would FORCE the rider to exert MORE effort in that sector in order to maintain what seemed to be a constant crank rotation speed - and that would do 2 things.
1) It would TRAIN the muscles to produce enough power/pedal speed to keep the cadence 'steady' during the deadspots. (and this is what I understand as the basis of your technique). And the 'training' might force the rider to apply power to the pedals as your theory suggstest.
2) By keeping the instantaneous speed more 'steady' it MIGHT be more effective (physiological efficiency is not known) than the SMALL cyclical changes in power application that occur during the 'deadspots' at 12 & 6 o'clock.
note: the amount of 'ovalness' would probably need to be quite small to avoid the need for excessive pedal effort variation during the deadspots.
Current theory about OVAL chainrings seems to be about reducing the TIME spend in the deadspot, and not about having smooth instanteous power producution DURING the deadspots.
Jay