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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 07-21-10, 02:46 PM   #1
Charles Ramsey
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stiffing up your chainrings

Here http://share.ovi.com/media/currentre...resident.10261 is a photo of universal chainrings bolted together to increase stiffness. These are pro neck and tuff neck chainrings with 110mm and 130mm patterns they are not really compatible with the 9 cog chain shown. I believe universal chainrings with 130mm shimano and 135mm campagnolo are also available under a different brand and I believe I have also seen 135mm campagnolo and 144mm campagnolo patterns but these were made for track bikes. This works and reduces the deflection of the large ring to about one half. I've run these with a missing bolt on the spider without any ill effects. Weight wenies can replace their steel bolts with aluminum bolts.
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Old 07-21-10, 04:26 PM   #2
Homeyba
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What's the point of doing that? Do you loose power because they flex a little? Maybe I'm missing something but it seems like a fix for a non-problem...
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Old 07-22-10, 08:26 AM   #3
Charles Ramsey
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What's the point of doing that? Do you loose power because they flex a little? Maybe I'm missing something but it seems like a fix for a non-problem...
If you are using a 54 tooth on a 110mm bolt circle the chainring can flex enough to derail the chain under a hard pull.
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Old 07-22-10, 10:01 AM   #4
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I have a 53 tooth ring and I am a fairly strong rider, but the most deflection I can get is a little chain rub on the derailleur cage! I am sure that this frame flex, not chainring bending.
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Old 07-22-10, 11:40 AM   #5
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Originally Posted by Charles Ramsey View Post
If you are using a 54 tooth on a 110mm bolt circle the chainring can flex enough to derail the chain under a hard pull.
Then you wouldn't need to replace a sketchy setup by another one as much as to use the right equipment (meaning a proper road crankset -- doesn't even have to be an expensive one).

It seems to me not as much as fixing a non-problem -- as Homeyba says -- but fixing a problem by a non-solution ;-)
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Old 07-22-10, 12:47 PM   #6
Ritterview
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What's the point of doing that? Do you loose power because they flex a little? Maybe I'm missing something but it seems like a fix for a non-problem...
Stiffer chainrings make for better FD shifting. I've got a selection of TA and FSA chainrings that were tried and failed on my crank, before the Dura Ace chainrings were installed, and now it shifts. At my tandem-savvy LBS they've found that tandems do better with the stiffer Shimano chainrings.
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Old 07-22-10, 01:31 PM   #7
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I run a 60T front chainring with a 11-28 cassette on my tandem and never had an issue? hmmm maybe I'm just not strong or fast enough.


My crank has 130mm bolt pattern so maybe that's why I don't have an issue...

Last edited by Homeyba; 07-22-10 at 01:35 PM.
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Old 07-22-10, 02:21 PM   #8
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Data points, for what they're worth.

1 - We've used 110mm BCD cranks with 54mm chain rings (Shimano, White Ind. & TA) for 13 years on two of the four road tandems we've owned during this time.
2 - Never once have we even given a thought to the possibility of throwing a chain off the 54t ring under power.
3 - Our two Erickson tandems were nearly identical, except that the '98 has 110 BCD spiders and the '02 had 130 BCD spiders. Both ran 54t chain rings and the performance/reliability was identical with zero issues.
4 - Never had any issues with the various different sets of Shimano, FSA, TA, or White Ind chain rings we've used on our seven different tandems, except when I've stuck new chain rings on and forgotten that they don't play nice with anything other than new chains.
5 - I don't shift our tandem's Front Derailleur while it's under a heavy load -- I employ a momentary soft pedal at the front while shifting -- as that's the easiest way to get crisp, trouble-free up and down shifts.
6 - We're not world-class / watt-generating monsters, but neither are 98% of the people who ride tandems.
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Old 07-22-10, 03:00 PM   #9
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Originally Posted by TandemGeek View Post
Data points, for what they're worth.

1 - We've used 110mm BCD cranks with 54mm chain rings (Shimano, White Ind. & TA) for 13 years on two of the four road tandems we've owned during this time.
2 - Never once have we even given a thought to the possibility of throwing a chain off the 54t ring under power.
3 - Our two Erickson tandems were nearly identical, except that the '98 has 110 BCD spiders and the '02 had 130 BCD spiders. Both ran 54t chain rings and the performance/reliability was identical with zero issues.
4 - Never had any issues with the various different sets of Shimano, FSA, TA, or White Ind chain rings we've used on our seven different tandems, except when I've stuck new chain rings on and forgotten that they don't play nice with anything other than new chains.
5 - I don't shift our tandem's Front Derailleur while it's under a heavy load -- I employ a momentary soft pedal at the front while shifting -- as that's the easiest way to get crisp, trouble-free up and down shifts.
6 - We're not world-class / watt-generating monsters, but neither are 98% of the people who ride tandems.
Your right on the money 1 through 6 and I can relate to 5 because I do the same and 6 being very correct about 98% of us.

Ride Safe,
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Old 07-23-10, 02:24 PM   #10
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The Sugino 53 tooth ring on our Burley had enough flex that we would throw the chain off doing Power Starts. (starting out of the saddle from a stop in the 53/11, as hard as you can).

Admittedly that was a rather severe test. Answer was stop doing that drill on the tandem.

Other than that we've never had trouble with a chainring flexing.
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