Chain tension between 2 chainrings on TANDEM - how???
07-04-07, 04:46 PM
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Sir Fallalot
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Chain tension between 2 chainrings on TANDEM - how???
So, this friend of mine has a tandem, and while I was oiling the chain, I was thinking, how is the chain between the captain's and the stoker's chainrings (on the left side) kept under tension? Anyone??
Must ask because that chain needs replacing.
Must ask because that chain needs replacing.
07-04-07, 05:03 PM
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There are several ways of accomplishing it. The most common is for the captain's botton bracket to be set in an eccentric which can be rotated to adjust the timing chain tension.
07-04-07, 05:21 PM
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Pwnerer
07-04-07, 05:37 PM
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On the Bike Friday Tandems you slide the frame apart. Probably not what yo have but an interesting and over complicated solution to a problem
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07-04-07, 11:44 PM
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Sir Fallalot
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Thanks guys. Well, since I would obviously notice a pulley (come on now, I was oiling the chains, not looking at the tandem from an airplane) or an ajustable frame, I will look for an eccentric BB as Grouchy proposed. But I am slightly skeptical, because I would have noticed an eccentric BB while oiling the chains on that tandem, I think.
Will keep you posted.
By the way, Rev. Chuck, I can imagine an ajustable frame does make some sense, in order to customize the length to the stoker - some may need a bit more real estate in front of them. Even a few cm more or less makes a huge difference.
Will keep you posted.
By the way, Rev. Chuck, I can imagine an ajustable frame does make some sense, in order to customize the length to the stoker - some may need a bit more real estate in front of them. Even a few cm more or less makes a huge difference.
Last edited by wroomwroomoops; 07-04-07 at 11:52 PM.
07-05-07, 06:58 AM
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Originally Posted by Rev.Chuck
On the Bike Friday Tandems you slide the frame apart. Probably not what yo have but an interesting and over complicated solution to a problem
07-06-07, 03:04 AM
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Visited my friend and checked more carefully: GROUCHY WAS RIGHT - it's an eccentric BB cup at the captain's end!
Regarding the floating/"ghost" chainring: I've done that with my first attempts at FG bike builds. Umm... maybe it works better for tandems, but with the FG I was working on, the ghost chainring kept flying off, at higher cadences. Not always, but often enough to scare me.
Regarding the floating/"ghost" chainring: I've done that with my first attempts at FG bike builds. Umm... maybe it works better for tandems, but with the FG I was working on, the ghost chainring kept flying off, at higher cadences. Not always, but often enough to scare me.
