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Drivechain Spring Tensioners - Future of the Shift Kit?
I did some hunting around online looking to see if there was a "left handed" or southpaw derailleur, and came up empty handed.
With the advent of springed tensioners being used on motorized bikes, it does make sense that a left handed/southpaw derailleur shouldn't be too far away.
A lefthanded cassette for driven sprockets I haven't been able find, so it would have to be modified onto a freewheel with lefthanded pawls, which would really be the easiest part of an undertaking such as this one. As well, the sprockets would have to be able to be spaced for 115 and other chains.
The last addition would be an idler pulley just before the drive sprocket to allow for a little play from left to right as you change gears.
I would really love to hear suggestions on this! Comments, suggestions, ideas, let's see if there's a possibility of this being at least prototyped as a community!
Last edited by DuctTapedGoat; 01-12-2011 at 05:21 AM.
08-28-2011 #2Motorized Bicycle Member
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- Upland CA
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funny enough i was dreaming up something similar the other night trying to fall asleep. i'd like to make a 3 speed cassette for our chain size or similar and a derailer but hadnt yet thought of a pully near the front gear to make sure it stayed aligned. great call on that. love to see someone do it esp if i can dream up something building on this.
now that i think about it. a jack shaft that stays on the same side and goes to a bmx size chain and a 6 sp. cassette locked in opposite direction with a locking ring on it so it doesnt pull itself off might work. with a single speed on the other side of the hub.
Early Raleighs had the chain on the left side. I guess they used Sturmey Archer hubs instead of derailleurs."I like moderation, in moderation" - Oscar Wilde
Sorry for bringing up an old thread but I had some thoughts on this matter.
You would need to alter the gear ratio of the new cassette. The SBP shift kit already changed the gear ratio to take advantage of the standard 10T to 36T cassette.
If you went straight from the motor's drive gear back then your lowest gear would be a 36T which is way higher a gear ratio than a standard 44T that comes with the kits.
You would need to either shrink the drive gear (almost impossible since its already a tiny 10T) or enlargen the cassette gears to be something like 30T to 50T variation...
With all that extra work and weight.... just get a shift kit.
04-19-2012 #5Motorized Bicycle Senior
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- Sep 2009
- Australia - Melbourne
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Maybe you haven't seen my solution regarding chain tensioners that operate with the shift kit. Been working to perfection for a long time now.
Sen me a PM and i'll send you a link that documents my designs.
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