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  1. #1
    45 miles/week Eggplant Jeff's Avatar
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    When I really stand on it, it feels like my fixie jumps teeth

    So I set up my fixie with all brand new stuff, new wheels, new cog, new cranks/BB/chainring, new chain.

    When I first test-rode it (like in the first couple hundred feet) it felt like the chain jumped a tooth or something, 2 or 3 times.

    Last night I went for my first significant ride (4 miles maybe?) and it did it once more. It only happens when I'm really mashing on the pedals.

    Is it something to do with the chain "breaking in"? I noticed after my ride that my chain, which was tight to the point of no slack (but not too tight, I followed Sheldon Brown's chain tightening instructions more or less) now has some slack in it (although not so much that I could really see the chain skipping, it's still pretty good... I've seen plenty of single speeds with more chain slack).
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  2. #2
    i am sure that i hate you spud's Avatar
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    check that the cog and lockring are tight and that the hub didnt move forward.
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  3. #3
    Senior Member shishi's Avatar
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    Sounds like your cog is slippin. REally mash it down and then tighten again and tighten lockring again. This is happened to me just this morning.

  4. #4
    Good Afternoon! SamHouston's Avatar
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    That'd be a strange thing IMO, and very hard to do, skipping teeth, even with an uberloosechain, plus you'd likely throw your chain.

    Sure it's not your cog slipping>? Or, for a similarly bad feeling, pulling the wheel forward in the dropouts? Both those generally occur when hammering.

  5. #5
    Good Afternoon! SamHouston's Avatar
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    doh!

  6. #6
    Elitist carleton's Avatar
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    I had the same problem with a SS conversion back in 2002. Whenever I would wrench the bike from side to side when pedaling hard the frame would flex changing my chainline slightly. Enough to make the chain bite and ride up on the the cog. I never really got it fixed.

    What frame, crankset, BB, and rear hub are you using?

  7. #7
    antisocialite dirtyphotons's Avatar
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    i think spud's onto something about the hub sliding up in the dropout.

    are you using quick release skewers? because if your hub is slipping, they might not be correctly applied. if not, do you have proper track nuts and lock nuts (these go directly inside your dropout).

    if your cog is loose, it shouldn't loosen your chain. i suppose it might be possible for a chain to stretch out a bit when first installed, but it shouldn't do so more than once.

    are you using a master link? if it wasn't properly installed, it could have snapped into place, loosening your chain.

    tighten it up again, if it gets loose again it's your hub slipping. if not, check back.

  8. #8
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    The only time I've had a slippage problem is when the cog was worn. I first noticed it standing on the pedals but it got worse and started slipping at other times. Replacing the cog fixed it every time.

  9. #9
    Senior Member john_and_off's Avatar
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    as some of these guys might remember, a few days ago i was having a similar problem - i wasn't sure if it was the chain skipping teeth or the cog slipping or whatever, but it only happened when, like you say, i was really mashing the pedals. i checked the cog and lockring, and they needed tightened, so problem solved for me. if you haven't already tried that, it's worth a look!

  10. #10
    45 miles/week Eggplant Jeff's Avatar
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    The locknuts are tight, the wheel didn't move that I can see (no fresh scrapes in the paint).

    By "cog slipping" do you mean that the lockring is not tight against the cog, so the cog can thread and unthread a small amount?

    I agree that ACTUALLY skipping a tooth on the chain seems extremely unlikely, that's just what it kinda felt like.

    I do have a master link but I'm pretty sure I installed it correctly (snapped together all the way).

    Frame: Steel early 80's Schwinn World Tourist... very large, not sure the exact measurement but I'm 6'4" and have almost no standover clearance. Rear wheel assembled came from Sheldon Brown, the black ones, I could probably find the link if you need it, but it was a specific fixed wheel, not a conversion. BB is the one he lists as "the perfect compliment to <whatever> crankset" on his fixie cranks page. The cranks are BulletProof BMX(I think) cranks.
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  11. #11
    dmc
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    make sure your wheel is cranked down tight... since they are "proper" track wheels it is probably not slipping around.

    when the cog slips, it means that the cog is not on as tight as it could be and when you mash the pedals you actually tighten the cog a little more. this causes the cog to spin and not the wheel for a brief second and may feel like you skipped a tooth. a good way to check this is to stop immediatly when it happens and check your lock ring. since you cog would now be tighter, you should be able to tighten your lock ring more and snug it up against the cog... this isnt that big of a deal and if you snug the lockring up once or twice it should eliminate the problem (since at some point the cog will be on tight enough that it will stop happening).

    it could be a problem if you keep riding after this happens because your lock ring is effectivly loose and this could result in stripping the hub.

    the best thing to do would be to rotafix your cog on there and then tighten he lockring down... this should get it tight enough that it wont slip. you can learn about rotafixing here

    (if this is not what is happening then its still probably a good idea to rotafix your cog on and tighen down the lockring before you ride it)

  12. #12
    Elitist carleton's Avatar
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    Quote Originally Posted by Eggplant Jeff
    but it was a specific fixed wheel, not a conversion.
    A "conversion" reffers to the frame being a road, touring, or MTB frame converted to track (edit: fixed-gear) use. It sounds like you do have a conversion.

    I still believe that the frame is flexing and moving your chain line. It only takes a few millimeters to throw the chainline off. Especially being that the frame is large. The frame of mine that had that issue was an older 60cm Trek 1000 Aluminum.
    Last edited by carleton; 06-09-06 at 09:58 AM.

  13. #13
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    Quote Originally Posted by carleton
    A "conversion" reffers to the frame being a road, touring, or MTB frame converted to track use. It sounds like you do have a conversion.
    though I agree with you; I always cring when I hear 'conversion'. A bike is fixed or its not.

    my unsoliticed, unrelated to this thread 2 cents.

  14. #14
    Elitist carleton's Avatar
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    Quote Originally Posted by dmc
    the best thing to do would be to rotafix your cog on there and then tighten he lockring down... this should get it tight enough that it wont slip. you can learn about rotafixing here

    (if this is not what is happening then its still probably a good idea to rotafix your cog on and tighen down the lockring before you ride it)
    Take that advice with a grain of salt. You should be able to get your cog and lockring on tight using proper tools. In my opinion, that Rotofix is a "in the field" emergency option.

    To determine if your cog is slipping:
    - Pedal hard until you feel it slip when pedaling forward
    - Continue pedaling forward
    - Jam the pedals back as if you were going to skid (you don't really have to engage a skid)
    - If the same slippage happens in the other direction, then the cog is slipping.
    - Take it to your local bike shop and have a mechanic who is familiar with fixies lock it down for you or buy the tools (chainwhip and lockring tool) and do it yourself.

  15. #15
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    I prefer rotafix because chainwhips are usually garbage. I just throw an old piece of tube between the Chainring and BB to keep the paint nice.
    Tighten down the lockring. Mash some sprints in a clear area, if/when the cog moves tighten the lockring. If you can't tighten the lockring enough to fix it (rare, but possible), there is a spacer you can put between the cog and hub.

  16. #16
    jooseyo Tangsooyuk's Avatar
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    Quote Originally Posted by Eggplant Jeff
    The locknuts are tight, the wheel didn't move that I can see (no fresh scrapes in the paint).
    Its still probably the wheel moving slightly in the drop outs instead of the cog slipping. Going with what you said about it slipping when you mash hard, the feeling you skipped teeth, then the chain being slightly slack all points to the nuts slipping. They dont need to move much to make the chain slack and the dropout would probably still looking like only one impression was made. If it was the cog it should slip when you apply back pressure then again when you mash and keep doing this, it also shouldnt make your chain slack. if you stretch a chain enough to make it slack in a 4 mile ride then you should throw it out.
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  17. #17
    Elitist carleton's Avatar
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    Proper Tools:

    Bottom Bracket Wrench (to remove lockring)


    Chain Whip (to remove cog)


    Lube

  18. #18
    jack of one or two trades Aeroplane's Avatar
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    Quote Originally Posted by carleton
    I had the same problem with a SS conversion back in 2002. Whenever I would wrench the bike from side to side when pedaling hard the frame would flex changing my chainline slightly. Enough to make the chain bite and ride up on the the cog. I never really got it fixed.
    +1, check your chainline. It feels like skipping chain when your chainring hits the sides of the chain too much. I learned this on my SS (bashguard was catching 1/8" chain).
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  19. #19
    45 miles/week Eggplant Jeff's Avatar
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    OK I'm going to go with the nuts slipping. If it were the cog, it should get worse, and it should happen both forward and backwards (only has happened forward). I tightened the cog on pretty well when I put the bike together.

    BTW, what's so hard about making a chain whip that's usable? I made one in like 2 minutes. Cut a length of old chain, screw it to a board. The board can be as long as you want. Mine was like 24 inches or so, I felt like I could EASILY have broken something with it (and not the whip... like, stripped the threads, twisted the hub in the spokes, something...).

    Here's some pics:



    P.S. I didn't know "conversion" was an official term, I just meant that it wasn't a multi-speed hub where I'd taken the cogs off and added a bunch of spacers... and it wasn't a SS freewheel hub without the lockring part.
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  20. #20
    Senior Member
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    My problem with chainwhips has always been removing cogs, not installing. I've never had a decent one though. I'll just keep on using the frame and wheel.

  21. #21
    Elitist carleton's Avatar
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    Quote Originally Posted by Eggplant Jeff
    OK I'm going to go with the nuts slipping.
    Tighten all you want, but I'll bet you a dollar that it's your frame flexing under pressure.

  22. #22
    45 miles/week Eggplant Jeff's Avatar
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    I'll let you know... But why would that loosen my chain?
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  23. #23
    45 miles/week Eggplant Jeff's Avatar
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    Quote Originally Posted by thurstonboise
    My problem with chainwhips has always been removing cogs, not installing. I've never had a decent one though. I'll just keep on using the frame and wheel.
    If you didn't live so far away I'd make you one... I've got plenty more of that chain left .
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  24. #24
    Elitist carleton's Avatar
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    Quote Originally Posted by Eggplant Jeff
    I'll let you know... But why would that loosen my chain?
    I would assume that if it only happened once, you were just breaking the chain in. But, if it happens every time, then I'm not sure.

  25. #25
    Electrical Hazard
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    Eggplant Jeff,
    NICE CHAINWHIP!

    Mine is made from a 27" flat cro-mo MTB bar, with a hole drilled 5" from the end for the chain to pass through.

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