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  1. #1
    Albany West Oz
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    1*9 with trials crank??

    I want to run a 20 or 22 chainring and a 11/34 cassette on ISIS BB. Would using a trials crank be a good idea, I am thinking about chainline. Is the positioning of the ring on a trials crank suitable or will it be set too far inboard as trials use single speed hub spacing??

    I need the easy gears for a fatbike build. Cheers.

  2. #2
    IllumaDucati
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    You'll get lots of ideas in this eleven-page thread: Show pics of your 1x9 setup

  3. #3
    g3h6o3
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    Trials cranks usually have the freewheel on the crank directly... You could simply ignore them I guess!
    Check out my SportTracks plugins for some training aid software.

  4. #4
    Albany West Oz
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    That thread looks good but is hard to open for some reason. Most set ups are running around 32 tooth chainrings which simplifies everything, ideas for running a single granny size ring is what I am chasing.

    True some trials cranks run a front freewheel but I was considering one that doesn't, such as a Middleburn.

    What confuses me is the definition of chainline, how does measuring from center of downtube to middle ring mean anything when there is such variation in BB width, what does 47.5mm mean when you are running a 100mm BB?

    Thanks anyways.

  5. #5
    Bicyclochondriac.
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    Quote Originally Posted by Freediver
    What confuses me is the definition of chainline, how does measuring from center of downtube to middle ring mean anything when there is such variation in BB width, what does 47.5mm mean when you are running a 100mm BB?
    .
    The measurement from the center-line (or center-plane, actually) of the bike to the middle (or single) ring is the one that matters when determining if the chain lines up well with the rear cassette, because the rear cassette is also usually a set distance from the center-line of the bike. How for a ring is from the outside of the bb shell is irrelevant to the chain trying to line up with a cog in the back.

  6. #6
    Albany West Oz
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    Okay, for anyone else that has had a few beers and is still wondering what all this means I recommend the Park Tools website, http://www.parktool.com/repair/readhowto.asp?id=110

    The irony here is that I am building up single chainring, flat peddle, fully rigid, no computer fat bike to regain the simple joy of cycling, and here I am struggling with chainline algorithms, anyhoo, I've ordered a middleburn trials crank with a 22... wish me luck.

    Another beer perhaps.....

  7. #7
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    Very nice crank....you'll love it. For $250 or $350 it should make you smile!

    A cheap way to do it is just use a 4-bolt mtb crank with a steel granny gear, and add the Truvativ trials-guard bash. It bolts to the 104mm holes and covers up to a 26T ring nicely.

    You don't need to worry about chainline very much since you're using a multi-gear chain...they flex quite a bit. When you're running singlespeed (with or without a singlespeed chain), that's when chainline really matters.

    You probably will need to find some method of keeping the chain on the front because the rear derailleur will allow some slack on impacts that might throw the chain. The Blackspire Stinger roller guide works very well, isn't up in your face like a full on chain guide, and it's cheap. Set up right, it'll keep your chain happy 98% of the time and works better than using a ghetto front derailleur. I run a similar 1x7 setup this way on my street rig and it only rarely drops the chain.

    A mid- or short-cage mtb rear derailleur will help, too...they have stiffer springs. The SLX is nice and not too expensive. An older Ultegra road model would work, too. If you use a long-cage with this set up, it'll work, but there will be more slack in the system when the bike bumps.

    cheers! more beer

  8. #8
    Albany West Oz
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    Cheers, I like the Middleburn, I have a triple on my Rush. The trials crank, spider and 22 hardcoat cost me 240 (aus dollars) from Chain Reaction in UK. If it all falls in a hole the cranks will adorn my next project and will only have cost me the spider.

    I was hoping that the position of the ring on the trials crank would be closer to the position of a middle ring than that of the granny, I would say in a day or two the postman will answer all my questions.

    Running a short cage X9 with gripshift to keep it clean on the bars.

    I am hoping the spider/bash will keep the chain from going outboard, to keep it from falling inboard I am waiting until it is all together and then see what I can run off the E-Type derailleur mounting post. The blackspire range is certainly on the menu.

    Hoping it all comes together, it is a great looking frame, a Fatback I have imported from Alaska, they twisted my arm and also sold me a pair of Hadleys, they do sound nice.

    Would be fair to say that I am getting a little enthusiastic about this build....

  9. #9
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    Sounds like a nice build.....especially the hubs! I don't have a Middleburn to look at but you should be fine with the cross-chain gears as far as noise/rubbing the bash. I'm using a Gusset one piece ring/bash on my setup and no issues...spacing is probably similar between the two. The chain will stay on most of the time but if you get on any rough trails or take drops over a foot or so, it may bounce off. On a 22t you won't have much tension from a Stinger guide (not much room for it until you hit the chainstay with the roller) but it'll help if you need to put one on there.


    Here's what I've been running (27t ring):


  10. #10
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    Thanks for this post! I'm trying to find a way to run a 26T 1x9 setup. Can't use a bashguard with the chain guide installed, so I've got the holes exposed from the 4 bolt Race Face crank. Want to clean up the look. BMX cranks and ring the way to go? Middleburn or Gusset? Any other recs?

  11. #11
    mtbr member
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    Quote Originally Posted by courtneya
    Thanks for this post! I'm trying to find a way to run a 26T 1x9 setup. Can't use a bashguard with the chain guide installed, so I've got the holes exposed from the 4 bolt Race Face crank. Want to clean up the look. BMX cranks and ring the way to go? Middleburn or Gusset? Any other recs?
    deity's new Vendetta V.3 cranks - http://www.deitycomponents.com/vendetta_crankarms.htm

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