Independent pedaling/coasting system
Independent pedaling/coasting system
(OP)
Can someone help me with some links to learn the drive mechanism of the 'Da vinci's independent coasting system' and/ or any other available independent pedaling or coasting system.





RE: Independent pedaling/coasting system
RE: Independent pedaling/coasting system
RE: Independent pedaling/coasting system
A lot of people see them on that da Vinci and assume that they somehow have independent gearing as well, and no, they don't- they're either pedaling at the same speed or one of them's not contributing. It just looks weird because they're not in phase with each other.
RE: Independent pedaling/coasting system
I wouldn't say that. There are significant gearing advantages- bikes with this system wind up having more distinct gears, a wider range, and smaller chainrings, all of which are tangible benefits.
For people who ride tandems on mountain bike trails, which a lot of people do, believe it or not. The stoker can adjust their cranks as necessary to clear obstacles, without the captain needing to stop adding power (or vice versa).
Lastly, for a rider combination with different levels of skill/experience, it means that the captain does not have to use his own power to drive the stoker's legs if the stoker wants to rest. This is significant.
RE: Independent pedaling/coasting system
Setting up a tandem with two freewheels is no big deal. The question becomes whether you want to give each rider their own gear ratios. I did one years ago where the rear rider could coast while the captain peddled, but the final drive ratio was the same for both.
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P.E. Metallurgy, Plymouth Tube
RE: Independent pedaling/coasting system
I had thought of, but not prototype - a tandem where the front drove a left-hand derailleur and left-hand chain and gear set, and the read drove a right-hand derailleur and gear set. On the back axle, both - or one or the other - would have the usual "coast" feature. Either then can pedal at different speeds and with different loadings.
RE: Independent pedaling/coasting system
The gearing would never be truly infinitely variable, but the stoker would have a few cadence choices to choose from in order to match output speed with the captain.
RE: Independent pedaling/coasting system
Sprag or over-running clutches can be used, as can conventional clutches.
Sprag - https://www.youtube.com/watch?v=Fsp3fm4KHs0
RE: Independent pedaling/coasting system
Here is the best execution of independent ratios that I have seen.
http://www.bilenky.com/#!viewpoint/cb9e
http://www.tandemseast.com/frames/bilenky.html
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P.E. Metallurgy, Plymouth Tube
RE: Independent pedaling/coasting system
I mentioned a friend had one. They love it, primarily for the independent coasting. And no, they don't go offroad. But that just doesn't strike me as a need. Yeah, if you had a bicycle where your right leg and left leg pedaled independently, somebody would like that, too, though.
On the "left derailleur"- very simple in concept. But tandems mainly use single-bike parts, they're already a small market, so there's a limit as to what you want to produce in the way of specialized parts for them.
RE: Independent pedaling/coasting system
RE: Independent pedaling/coasting system
Theoretically, if that's not an issue, you should be able to put different size timing sprockets so that the stoker always pedaled faster (or slower) than the captain. But I've never seen anyone do that, either. If there's too much of a cadence mis-match, it's better to just ride your own bike.
It would be an intriguing experiment to build a conventional bicycle where the left and right pedals went at different speeds. Presumably, you'd need clipless pedals or a fixed gear bike for those awkward both-pedals-down moments. It just might be exceedingly irritating to ride, too.
RE: Independent pedaling/coasting system
RE: Independent pedaling/coasting system
RE: Independent pedaling/coasting system