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Discussion Starter #1
Consider the following changes to a standard mountain bike:

0. Use a gear box or internal gear hub instead of derailleurs. Besides the well known advantages (impact tolerance, debris resistance, straight chain line) and disadvantages (weight, efficiency, cost), there's another advantage: bidirectional torque.

1. Eliminate the freewheel/freehub ratchet, and replace it not by a fixed drive, but by a clutch. Use a twist grip on the left handlebar to control the clutch, like motorcycles use right grip twist for throttle.

By making those two changes, you get the main advantage of a fixie: bidirectional torque. Yet you avoid the disadvantages of a fixie, since with the GB/IGH, you still have multiple gears, and by disengaging the clutch, you still have the ability to freewheel.

There's another minor advantage: while freewheeling, there's no ratchet noise.

There's one new disadvantage: to freewheel, you can't just stop pedaling. You have to disengage the clutch.

Available GB/IGH products don't provide neutral, since it's unnecessary when used with a freewheel/freehub ratchet. But neutral could be provided with little or no weight or cost increase. With it, freewheeling for long periods wouldn't require holding the clutch disengaged.

Thoughts?
 

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Discussion Starter #2
Considering my other idea in "How about a twist grip for the rear brake?" in the Brake Time subforum, which would free up a lever, that lever could be used instead for the clutch. If your brakes are set up moto-style (right front, left rear), then this gives:

right lever: front brake
left lever: clutch
left twist grip: rear brake

If you train yourself for this, it has the added advantage that your bicycle and motorcycle muscle memories become compatible; you'll never grab the wrong control. On a standard motorcycle, the worst that happens is you try to twist the left grip for rear brake, and nothing happens.
 

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Just stop posting nonsense- there isn't a single advantage to anything you're posting.
 

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The sprag-clutches used in a lot of internal gear hubs and the pawls that engage the different gears might give you issues when trying to transmit power in the opposite direction to normal.
 

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Just stop posting nonsense- there isn't a single advantage to anything you're posting.
Give the guy/gal a break, shouldn't discourage free thinking.
However, I don't see much advantage except for specialized riding, aka trick riding. Neutral is helpful in rolling in reverse while keeping cranks/legs still. Freestyle guys do this with freecoasters, or you can find a few vids of guys who put a blank space on cogset making a neutral you can shift chain to.
Being able to apply torque in reverse like a fixie is also limited practicality, not many people use this. Again trick riders, cycleball, circus, track (although track events I think you're actually not allowed to go in reverse, its more for braking without brakes).
It's not like your engine (legs) are constantly running, so you don't require a clutch/neutral.
You could come to a stop into a track stand and sit there and spin your cranks like a madman.
 

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Give the guy/gal a break, shouldn't discourage free thinking.
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You could come to a stop into a track stand and sit there and spin your cranks like a madman.
Agreed. It's an idea, good or bad the O.P. is thinking outside the box. Even if the idea doesn't work out in the end it might give someone else another idea that will work out.

Re the clutch idea - you could rev up your legs then drop the clutch! ;-)
 
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