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  1. #1
    It's carbon dontcha know.
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    Drivetrain "slips" when I stand to crank uphill.

    I've a problem that my drivetrain "slips" sometimes when I stand and crank. It only does it a minute amount but it worries me that I might drop the chain and smack a knee into my stem. I really don't know what's causing it, but I'm more familiar with geared bikes so I'm open to suggestions. The chainline appears perfect, the hanger is straight. I don't have any problems with the rear wheel when I run it on a geared bike.

    Setup:
    '06 Fisher Paragon 29er
    Stylo 1.1 Oct crankset
    Boone 20T cog
    Hope geared hub with spacers.
    Dura-ace chain
    Forte tensioner



    Thanks.

  2. #2
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    Quote Originally Posted by 6thElement
    The chainline appears perfect
    Thanks.
    Try using a plumb bob...easier to tell.

  3. #3
    My spoon is too big!
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    Have you tried modifying the tensioner to pull up, instead of down? The extra chain wrap on the cog might help.
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  4. #4
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    alignment...

    Quote Originally Posted by 6thElement
    I've a problem that my drivetrain "slips" sometimes when I stand and crank. It only does it a minute amount but it worries me that I might drop the chain and smack a knee into my stem. I really don't know what's causing it, but I'm more familiar with geared bikes so I'm open to suggestions. The chainline appears perfect, the hanger is straight. I don't have any problems with the rear wheel when I run it on a geared bike.
    Thanks.

    1 thing you can check is to make certain that the Tensioner Pulley is also perfectly IN LINE with the Cog as that could cause an issue under Torque.
    I would almost bet the Tensioner is somehow to blame for your issue if you think your Cog to Chain alignment IS OK.

  5. #5
    Retro Grouch
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    Quote Originally Posted by 6thElement
    I've a problem that my drivetrain "slips" sometimes when I stand and crank. It only does it a minute amount but it worries me that I might drop the chain and smack a knee into my stem. I really don't know what's causing it, but I'm more familiar with geared bikes so I'm open to suggestions. The chainline appears perfect, the hanger is straight. I don't have any problems with the rear wheel when I run it on a geared bike.

    Setup:
    '06 Fisher Paragon 29er
    Stylo 1.1 Oct crankset
    Boone 20T cog
    Hope geared hub with spacers.
    Dura-ace chain
    Forte tensioner



    Thanks.
    The usual suspect is the chain tensioner; the reason it fails is known, why it only fails on some bikes is unknown. First check to see your chain is a short as possible. Failing that, switch the tensioner to a push-up mode and use a zip tie to hold it in place. Otherwise, you may want to go to a set screw style tensioner.
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  6. #6
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    Quote Originally Posted by aka brad
    First check to see your chain is a short as possible.
    Yea, what he said...

  7. #7
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    From the picture it's definitely the tensioner. If you look at the cog as if it's a clock the chain is only touching from about 7 o'clock to 1 o'clock. There's not enough chain to cog contact which will make it "slip" under a load. Work with the tensioner & you'll be fine.
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  8. #8
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    My take is also the tensioner - as you torque down your pedal, upper chain gets stretched to max, and this will slacken the bottom chain At that point, the tensioner will further "open" down, reducing the chain wrap on your cog further. Under a heavy load, it tends to skip on rear... I hacked my Forte (mmm, yeah) tensioner to get more wrap and also lost some weight ):



  9. #9
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    Don't use a spring tensioner!

    Why do people insist on continuing to use a spring to set their chain tension? It's like saying "YES! I've finally gotten rid of my hideous cow of a girlfriend, but I'm still not going to hang out with my friends, drink beer, have fun, or pick up women."

  10. #10
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    Quote Originally Posted by bad mechanic
    Don't use a spring tensioner!

    Why do people insist on continuing to use a spring to set their chain tension? "
    Probably b/c when used properly & adjusted correctly they actually WORK!

  11. #11
    meatier showers
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    A rear derailleur is a spring-type chain tensioner. Best sprung tensioner I've ever used, in fact.

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  12. #12
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    Quote Originally Posted by farrisw1
    Probably b/c when used properly & adjusted correctly they actually WORK!
    Even when used properly and adjusted correctly they're inferior to a rigid tensioner since they'll still bounce around, and can release tension on the chain. Plus, you can still get the chain bouncing off the chainstay.

    Rigid tensioners simply work better with fewer problems, and they cost the same.

    The only time to use a spring tensioner is when using a full suspension design with a variable chain length.

  13. #13
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    i'd like to hear if the OP has found his solution for the problem because i''m having the same issue with my new setup:

    Surly chainring 34t
    Surly Cog 17t
    Surly singulator chain tensioner in push down modus
    8 speed shimano ig chain
    Cannondale Caad3 xl frame

    if anyone has any advice..

  14. #14
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    I guess I was just lucky or somehow chose the perfect components that worked...my spring tensioner, which came with a "no name" $20 SS conversion kit off ebay, worked flawlessly during the time I used it. I will say that I had to remove a link or two post initial build up to acheive the flawless operation. Understandably though, not everyone's specific situation is the same and results will of course vary.

  15. #15
    I have red hair
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    Quote Originally Posted by Sparticus
    A rear derailleur is a spring-type chain tensioner. Best sprung tensioner I've ever used, in fact.

    --Sparty
    that's why they put them on geared bikes, cause they don't work so hot on single speeds...

    technically a derailleur is a spring and cable sprung tensioner that you adjust on the fly by increasing or decreasing the amount of tension, thus shifting into different gears. so on a single speed, where you don't want/need/have different gears, a cable/spring or spring style tensioner might not be the best option since you don't want the tension on the chain changing at all.

    I am not a fan of the spring style tensioners, i got a SS to get rid of the dangly things on my bike...
    "I don't believe in brakes, all they do is slow you down"

  16. #16
    It's carbon dontcha know.
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    The chain is as short as I can go without using a half-link. I'll take a look to see if I can convert to push-up mode, but I think I would get tensioner/cog interference.

  17. #17
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    Quote Originally Posted by paradigit
    i'd like to hear if the OP has found his solution for the problem because i''m having the same issue with my new setup:

    Surly chainring 34t
    Surly Cog 17t
    Surly singulator chain tensioner in push down modus
    8 speed shimano ig chain
    Cannondale Caad3 xl frame

    if anyone has any advice..
    Again this is a common problem on some bikes. The Singleator comes with a push up spring, which should solve the problem.
    Just one more rep and I get the toaster!

  18. #18
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    Quote Originally Posted by farrissw1
    I guess I was just lucky or somehow chose the perfect components that worked...my spring tensioner, which came with a "no name" $20 SS conversion kit off ebay, worked flawlessly during the time I used it. I will say that I had to remove a link or two post initial build up to acheive the flawless operation. Understandably though, not everyone's specific situation is the same and results will of course vary
    I wouldn't say you are lucky (you might be in other things, but I don't know about that), I would say 6thElement just fell into the 10% or so where the spring tensioners don't work.

    Quote Originally Posted by 6thElement
    The chain is as short as I can go without using a half-link. I'll take a look to see if I can convert to push-up mode, but I think I would get tensioner/cog interference.
    Red Green is right when he recommends a dérailleur as a tensioning device. It not only tensions the chain, but holds the chain over the cog. If you look at a dérailleur in use, you will see, even with the tensioning arm extended out to take up a long length of chain, the jockey pulley maintains sufficient chain wrap.

    Here's the long reason why your chain is skipping (just skip past if your not interested). Most spring tensioners work by pushing the chain down and away from the rear cog. This results in very poor chain wrap. When peddling the majority of the torque from the chain is on the front chainring is on the teeth at 12:00 –0300 and on the rear cog it is the teeth from 6:00- 9:00. What this means is the very area of the rear cog where, chain wrap is necessary, a push down spring tensioner pulls the chain off the cog. This transfers the torque to the tensioner pulley wheel, which in turn pulls the tensioner arm upward. The chain then rides up in the cog teeth in the 9:00-12:00 position. Since it takes a great deal of torque to turn the rear wheel and there is practically no chain warp in the area, the tensioner will fail and the chain will jump over the teeth at the 9:00-12:00 position on the cog, causing it to “skip”. The answer is to first make sure your chain is as short as possible (a half link is a good idea but it will create a weaker link). Next use a spring tensioner with a push up mode or even better a tensioner without a spring so the arm can be locked up; this way tensioner cannot be defeated by overcoming the spring tension.

    So, if the push-up mode hits your chain stay, then I would go with either a set screw style tensioner like this Sette or the ubercool Yess ETR-B.
    Just one more rep and I get the toaster!

  19. #19

  20. #20
    It's carbon dontcha know.
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    I've had a play around, with my 32/20 combo I could maybe shorten the chain with a half link. With my current config there's too much slack to use a push up, the tensioner would hit the cog.

    Too many logs where I ride to use the tensioner up front, I might have to give the Sette model a try.

    Thanks for the suggestions and help.

  21. #21
    Monocog Masher
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    Besides your tensioner issues, I would also recommend some rings from Niner. They are much taller and wider than most and they don't have ramps. A track chain is another cool SS accessory that may help keep your drivetrain bullet proof.

  22. #22
    meatier showers
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    Quote Originally Posted by RedGreen
    that's why they put them on geared bikes, cause they don't work so hot on single speeds...
    ...
    I am not a fan of the spring style tensioners, i got a SS to get rid of the dangly things on my bike...
    Me too. I haven't used a rear derailleur as a chain tensioner since I did my first SS conversion over ten years ago. And I didn't like the drivetrain friction that came with it. Didn't mean to imply that it was optimum for tensioning a chain, only that it works well for eliminating chain skipping because it increases chain wrap. That's all I said and all I meant to say.

    FWIW I've employed EBBs, ghost rings, Singlators, rear derailleurs, track ends, semi-horizontal dropouts as chain tensioners over the years. I prefer a non-sprung tensioning system. But I stand by what I said... a rear derailleur is the best sprung chain tensioner I've used. Please don't read any more into it than that. You won't find a rear derailler on any of my singlespeeds.

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  23. #23
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    Listen!

    Quote Originally Posted by aka brad
    Again this is a common problem on some bikes. The Singleator comes with a push up spring, which should solve the problem.
    well i finally solved my problem, and it had nothing to do with tension.. it was the sram 8 speed powerlink which wouldn't let go of the Surly cog nicely.. strange eh?

    i removed it from the chain and linked it together again with the supplied shimano pin, problem solved.

    so if anyone was planning to use an 8 speed sram powerlink on a surly cog, be warned..

  24. #24
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    Quote Originally Posted by paradigit
    well i finally solved my problem, and it had nothing to do with tension.. it was the sram 8 speed powerlink which wouldn't let go of the Surly cog nicely.. strange eh?

    i removed it from the chain and linked it together again with the supplied shimano pin, problem solved.

    so if anyone was planning to use an 8 speed sram powerlink on a surly cog, be warned..
    Makes sense, single speed cogs are much thicker than a 8 speed cog you would find on a normal cassette.
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  25. #25
    master blaster
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    maybe your cog is to close to the edge of the cassette body and isnt getting the grip it needs? any close up pics of cog alignment?
    Quote Originally Posted by ISuckAtRiding View Post
    The dude is like 120lbs, tops lol he can run any tires he wants without issues, i'm sure.

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