Originally Posted by
cydewaze
Back to the subject of bikes, what about a CVT drivetrain? The rider would have some sort of control to dial in his or her preferred cadence. and the bike would vary the gearing to always keep it there. It would be like a fixie/SS but you'd have an infinite range of gears. Have everything done in the rear hub, and a single chainring. If you're going to make gear shifting automatic, I'd prefer something like that.
People have been working on this but their main problem is getting the weight down in the rear hub where this transmission is located.
Cycling | Fallbrook Technologies Inc.
You can buy one and try it for yourself.
As I said earlier, I rode a 3-speed automatic cruiser bicycle back in the early 80's. Fine for flat roads where one would usually ride a cruiser. Not so good on hilly dirt roads.
The Dancing Chain has pictures of automatic cranksets
And there's been the 2-speed Fictel and Sachs and Bendix hubs where you back pedal to shift gears for about 100 years now, IIRC.