I am almost certain the phaser gearbox from Pedal Motive by Nickolas Hein has been discussed before, but I am unable to find the posts. I completely understand this gearing wouldn’t solve every option or be suitable in all applications, but as far as I understand it should work with dual pedal direction. A 3-4 speed version could be created for a jackshaft version or a full version with a chain running outside the tyre such as the Sturmey archer 3 speed. Find the video below on the Facebook link. Would love some links to the threads if already discussed or your input below. Thanks
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I think you’d just end up with the chain binding in weird and wonderful ways.
It’s not clear whether there’s a spung idler on the bottom of the gear change slider mechanism, but I suspect for this to work there must be, which is incompatible with it being driven in both directions.
There should ideally be a tensioner somewhere, but in principle, you could make this work in both directions with comparatively little play if you stick to small jumps between sprockets and put a sprung tensioner on either side
I think it’s an interesting concept if someone wanted to make a jackshaft uni, but not sure if you could make it have desirable characteristics, even if it works without binding issues. It only works with small jumps between gears, so you would probably need to make a 7 or 8 speed version to get a desirable gearrange. I’d tend to believe that having to do less gearchanges is better, since even with perfect shifting any gearchanges is a moment of insecurity.
The force of pedalling would easily overcome any spring tensioner, and then those springs would add massive amounts of play making balancing very difficult as you wouldn’t be able to apply any backwards correction force while riding forwards.
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I’m aware, but with small gear jumps, you don’t need a lot of slack. There is no chance that there is as little play as a Schlumpf hub, but I think it may be possible to limit it to an amount is just about usable.