homemade derailleur transmission?
- Thread starter jazz2561
- Start date
David Staton once did something similar to what you have. He put a 7 speed freewheel on one of his outside drive gearbox. There was a single sprocket on the left side of the rear wheel. He designed a shifter for it as well. I see he no longer carries this kit. So I'm going to assume it either didn't sell well or didn't work well. You may be able to design your system to work but at what expense?
well I went ebay and mfg supply and I can possible build this transmission for 50 to 80 dollars easily, if do a redesign even lower
Hey for that price I say go for it. I was told my autoshift bike wouldn't work either. Yet this is going on my forth year riding it. I'll soon be building a 5 speed automatic using a Strumy Archer 5 speed hub.
Give it a whirl, why not I figure & it will definitely work lol, it's for how long I wonder about is all, they're temperamental & comparatively delicate even in the best of situations - then again an $80 experiment is worth every penny even if it turns out to be no more than a learning experience.
Some stuff I've learned - chain whip/slap can be an issue at the higher speeds we have - a stronger or additional return spring may aid this & if you use a thick/tacky lube or cheap chain the links may bind, snarling in the derailleur & ripping it apart. If the power application is too abrupt (engagement/torque) the freewheel pawls may fail and/or sheer teeth off the cogs. Oddly, chain/cog wear doesn't seem to be a problem but the potential for the occasional catastrophic failure shouldn't be dismissed as even a slight maladjustment can have grave consequences (chattering between gears/indexing failure can and will cause serious damage w/this load).
Example of (mild) chain whip w/a new chain & fresh, light lube during one of the seemingly endless indexing sessions: http://youtu.be/_GTS0xG8BPM
This design of yours looks promising, I would hazard the guess that you may have issues with the "input shaft" to "gears with derailleur" chain as it looks quite short, the closer the two points the greater the angle the chain has between it's lowest & highest gears, causing indexing issues and problems with the chain skipping off the forward cog;
...and I would remind some there's a difference between saying "it can't be done" and advising of problems that have been experienced, between nay-saying and trying to help.
Some stuff I've learned - chain whip/slap can be an issue at the higher speeds we have - a stronger or additional return spring may aid this & if you use a thick/tacky lube or cheap chain the links may bind, snarling in the derailleur & ripping it apart. If the power application is too abrupt (engagement/torque) the freewheel pawls may fail and/or sheer teeth off the cogs. Oddly, chain/cog wear doesn't seem to be a problem but the potential for the occasional catastrophic failure shouldn't be dismissed as even a slight maladjustment can have grave consequences (chattering between gears/indexing failure can and will cause serious damage w/this load).
Example of (mild) chain whip w/a new chain & fresh, light lube during one of the seemingly endless indexing sessions: http://youtu.be/_GTS0xG8BPM
This design of yours looks promising, I would hazard the guess that you may have issues with the "input shaft" to "gears with derailleur" chain as it looks quite short, the closer the two points the greater the angle the chain has between it's lowest & highest gears, causing indexing issues and problems with the chain skipping off the forward cog;
...and I would remind some there's a difference between saying "it can't be done" and advising of problems that have been experienced, between nay-saying and trying to help.
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