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My crank arms are not aligned.

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My crank arms are not aligned.

Old 04-07-20, 08:22 AM
  #1  
Fatherof2
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My crank arms are not aligned.

Hello All,

The crank arms on my Trek T200 are not in alignment. (Meaning that when my right foot is all the way down for example, my stokers foot is not.)

How do I fix this? Is it an easy fix? Best left to the LBS? Am I causing damage?

Thanks All!
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Old 04-07-20, 08:46 AM
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Carbonfiberboy 
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Should be an easy fix. Your captain's bottom bracket is mounted in an eccentric. That eccentric needs to be loosened and rotated so as to loosen the timing chain. Then you adjust the chain so the cranks are aligned and retighten the eccentric and check the crank alignment again.

That eccentric loosens and tightens in various ways, depending on what tandem you have. There's a good article on all this here: https://www.sheldonbrown.com/synchain.html

There's a decent possibility that your eccentric has not been moved in a very long time and thus it is a bit corroded and frozen in position, which is probably a bike shop job..

Tandems require a good bit more maintenance that a single bike because there's more stress on everything, because they are more complicated, and because the cables are much longer. There are two approaches to tandem maintenance. Some folks take it to the bike shop for everything and never work on the bike themselves. Thriftier folks have a work stand and do most of the maintenance themselves, which is a learning process, but as the above article shows, there's a lot of info available on the web and google is your friend.
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Old 04-07-20, 09:01 AM
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Some teams like to have the pedals out of phase. If you read the same Sheldon article he talks about Phase here: https://www.sheldonbrown.com/synchain.html#phase
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Old 04-07-20, 09:24 AM
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^True, but in all my years of cycling, I've only seen one tandem 90 out of phase (OOP), for the very good reasons stated in the Sheldon Brown piece. I can't remember if he mentioned that the team can't stand on an out of phase tandem. However, I take it that in the OP's case, the crank arms are maybe only a couple teeth out of alignment, possibly because as was also mentioned in the article, some captains prefer their downstroke to happen just before the stoker's, thus pulling the stoker's foot over the top of the pedal stroke. This is more common with teams in which the stoker is new to cycling or not nearly as strong as the captain. That said, my stoker is much weaker than I, but we have our cranks exactly in phase because if feels better than way. My stoker absolutely loves riding the tandem, so I think we're doing it right, for us.
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Old 04-07-20, 01:14 PM
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If the timing chain is appropriately tight (i.e. lose enough to not bind, and deflects about 1/2 inch when you press on it with your finger), you can adjust the timing of the two cranks without moving the eccentric. Derail the timing chain by pressing on it side ways as you turn the cranks, just as a deraiileur would.

Then line up both cranks parallel to the ground. Reinstall the chain, keeping the cranks in the same relative position, and you're done.
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Old 04-07-20, 06:33 PM
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Have you tried a few rides first to see how it goes? Mine came that way and the wife and I ride great with that setup...there is constant power and less stress on everything. We are by no means racers, so may depend on how extreme you ride the bike.
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Old 04-30-20, 02:56 PM
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Thanks All!

Thanks Merlin!

Worked like a charm.

So simple............I feel dumb for not thinking of that.

D.
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