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    Adjusting chainline

    Hi,

    I am looking at buying this hub: http://www.planet-x-bikes.co.uk/i/q/...2h-black-135mm and was wondering how easy it would be to adjust the chainline.

    I will be using it to convert my triple speed hybrid to fixed, and although the chainline seems ok from my measurements it may need minor adjustment.

    Thanks

    Daven

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    Senior Member Kayce's Avatar
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    The hub doesnt effect chain line adjustment. What matters is your rear drop outs(where the back wheel attaches to the frame) If you have the style that the wheel pulls straight down from a fixed gear conversion is just about impossible, with out getting a specialty hub. But if there is room to slide the wheel back and forth you will be just fine, no matter what fixed hub you get.

  3. #3
    Veteran Racer TejanoTrackie's Avatar
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    Quote Originally Posted by Kayce View Post
    The hub doesnt effect chain line adjustment. What matters is your rear drop outs(where the back wheel attaches to the frame) If you have the style that the wheel pulls straight down from a fixed gear conversion is just about impossible, with out getting a specialty hub. But if there is room to slide the wheel back and forth you will be just fine, no matter what fixed hub you get.
    You're confusing "chainline" with "chain tension." The OP is concerned with chainline, which is the lateral alignment between the cog and the chainring.
    What, Me Worry? - Alfred E. Neuman

    Quote Originally Posted by Dcv View Post
    I'd like to think i have as much money as brains.

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    Quote Originally Posted by daven1986 View Post
    I will be using it to convert my triple speed hybrid to fixed, and although the chainline seems ok from my measurements it may need minor adjustment.
    Have you measured the chainline for the chainring position on that triple crank you will be using?

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    Senior Member Kayce's Avatar
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    You are correct, I misread the post. My mistake.

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    Quote Originally Posted by HardyWeinberg View Post
    Have you measured the chainline for the chainring position on that triple crank you will be using?
    yeah, it is 50mm from the middle chain ring to the centre of the frame. the reason I ask is that I'm sure some adjustment will be required and if the hub is 135mm and my drop outs are 135mm I was wondering how one can fit washers in!

    thanks

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    Veteran Racer TejanoTrackie's Avatar
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    Quote Originally Posted by daven1986 View Post
    yeah, it is 50mm from the middle chain ring to the centre of the frame. the reason I ask is that I'm sure some adjustment will be required and if the hub is 135mm and my drop outs are 135mm I was wondering how one can fit washers in!
    You can add or delete axle spacers to make the hub spacing correspond to the dropout spacing, which in your case they already do. If you add spacers to make a hub wider, then you can place more spacers on one side than the other to move the cog position either inboard or outboard. However, it looks like your hub already has wider flange spacing, such that it does not have extra spacers, and therefore you cannot do this. So to make a long story short, you cannot make adjustments in chainline with that particular hub, and must rely on chainring position to accomplish this. If your chainring cannot be adjusted properly on any of the crank spider positions, then your only recourse is a different bottom bracket spindle that is either longer or shorter.
    What, Me Worry? - Alfred E. Neuman

    Quote Originally Posted by Dcv View Post
    I'd like to think i have as much money as brains.

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    Even if you could adjust the chainline on the hub, you wouldn't want to. It would require re-dishing the wheel asymmetrically, which would weaken the wheel.

    But I don't understand. It says on that page the hub has a 50mm chainline, and you just said your chainring is 50mm from the centre of the frame. What exactly is the problem?
    I have a front brake, but I only use it for slowing or stopping.

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    Quote Originally Posted by TejanoTrackie View Post
    You can add or delete axle spacers to make the hub spacing correspond to the dropout spacing, which in your case they already do. If you add spacers to make a hub wider, then you can place more spacers on one side than the other to move the cog position either inboard or outboard. However, it looks like your hub already has wider flange spacing, such that it does not have extra spacers, and therefore you cannot do this. So to make a long story short, you cannot make adjustments in chainline with that particular hub, and must rely on chainring position to accomplish this. If your chainring cannot be adjusted properly on any of the crank spider positions, then your only recourse is a different bottom bracket spindle that is either longer or shorter.
    Thanks for the info

    Quote Originally Posted by zacked View Post
    Even if you could adjust the chainline on the hub, you wouldn't want to. It would require re-dishing the wheel asymmetrically, which would weaken the wheel.

    But I don't understand. It says on that page the hub has a 50mm chainline, and you just said your chainring is 50mm from the centre of the frame. What exactly is the problem?
    The problem is that the measurements might be out by 1mm or so, because it is pretty hard to measure to the middle of the frame 100% accurately (or at least I find it is). I don't mind having to re-dish the wheel because it doesn't make that much difference to the strength (look how dished a geared wheel or a disc brake wheel is), I have both and they cope fine with the terrain around here (even if it is potholed!).

    I guess I will just go for the hub and hope it works out! Will measure the chainline before building the wheel though!!

    Thanks again guys

    Daven

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    Veteran Racer TejanoTrackie's Avatar
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    +/- 1mm is negligible and insignificant. Unless you have problems, don't worry about it.
    What, Me Worry? - Alfred E. Neuman

    Quote Originally Posted by Dcv View Post
    I'd like to think i have as much money as brains.

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    Thanks, I have found bottom bracket spacers that apparently can be used to space the cog slightly, so that is an option if it needs to be moved out a bit.

    Thanks for the advice

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