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  1. #1
    Senior Member TrackMonkey7's Avatar
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    What is wrong with my drivetrain?

    While spinning my bike on the trainer, I noticed a lot of 'play' in my chain. At first, I saw that it gained and lost slack with each crank revolution:
    http://youtu.be/i9emufhtC0k

    Then, I noticed that when looking at the chain from above and behind there's a reasonable amount of play laterally:
    http://youtu.be/jlRhNP0koaI
    http://youtu.be/y1E3kiX-pkQ

    I've had this chain, a cheap KMC Z410 since I put the bike together for some time, perhaps . I used to have an All-City crankset, which I've since replaced with a SRAM Omnium. Given the Omnium's 'unique' qualities, I figured that this may have been caused by an off-center spider. When I spun the crank with no chainring, the spider arms weren't noticeably off-center. My FSA rings are very round, with not enough deviation to make the chain flex like this. I have an All-City ring that isn't as round as the FSA ring, but even that is only a millimeter out of round at most. The rear hub in the videos is an older Surly track hub, with loose ball bearings. The cones are a little loose right now, and they aren't centered perfectly on the hub meaning that the chainline is probably a little off. However, I have a set of wheels with sealed bearings, with no such cones to adjust and I still have similar issues. I'm wondering if it could be the fact that my All-City cogs aren't as wide as say, Dura-Ace cogs, again throwing off the chainline:


    (All-City on the left, Dura-Ace on the right)

    Finally, I'm wondering if the chain itself could be the culprit. Though there are no stiff links, I didn't use the master link, and thus reinserted pins once or twice (I may have trimmed the chain down a couple of times).

    NB: I'll feel very silly indeed if this is just a typical symptom of a chain that's too tight.

  2. #2
    Elitist carleton's Avatar
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    It looks fine to me. Is the chain coming off?

  3. #3
    Senior Member TrackMonkey7's Avatar
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    No, it's tighter than I've seen a lot of people keep their chains, though not so tight as cause undue friction. Would this tightening and loosening of the chain accelerate wear on the cogs and rings?

  4. #4
    Elitist carleton's Avatar
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    Quote Originally Posted by TrackMonkey7 View Post
    No, it's tighter than I've seen a lot of people keep their chains, though not so tight as cause undue friction. Would this tightening and loosening of the chain accelerate wear on the cogs and rings?
    Some surging is normal.

    In what order do you tighten your chainring bolts? One after the other or star-shape? Star shape is recommended to keep this from happening.

  5. #5
    Senior Member TrackMonkey7's Avatar
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    Interesting. I'd had no idea that the pattern I tightened the bolts could have any effect. I usually do it in a star pattern because I'd heard that I should, but never knew why. Lately I've been more complacent about it and have been doing it in order. I'll have to do it in a star pattern from now on.

  6. #6
    Elitist carleton's Avatar
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    If it makes you feel any better, I just checked my track bike for surging.

    My setup: SRM track cranks, Sugino Zen chainring (set using star pattern), Izumi V chain, Dura Ace cog, Dura Ace high flange hub...same surge as you note in your video

    You are fine.

  7. #7
    Senior Member TrackMonkey7's Avatar
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    Quote Originally Posted by carleton View Post
    You are fine.
    Sweet. Thanks, Carleton!

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