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  1. #1
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    Rear wheel replacement, positioning problem

    Hi guys,

    As my postcount and next question tell you, I'm a total newbie when it comes to bicycle mechanics.

    So, I have just taken out the rear wheel (with hubgear) of my old second hand bike because it was damaged beyond repair. I have now bought an almost identical replacement wheel, also with a 3-gear hub (Sturmey-Archer).
    I tried to put it back into position but this just drives me crazy. It seems as if my chain is shorter than before (however I use the gear wheel of the old bike, so nothing has changed) because I can't get the rear wheel axle to the end of the (semi-horizontal)dropout and thus making it very hard to position the wheel straight.

    So my basic question is: do I have to get this axle to the end of the dropout?
    If yes, how?
    If no, how do I make sure that my wheel is positioned straight?

    Oh, also the wheel has no quick-removal levers, it only uses bolts to tighten. If any other info is needed, I'll be glad to do so. Sorry if there are terminology mistakes, I'm not a native speaker...

  2. #2
    Senior Member
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    The axle should not go to the end of the horizontal dropout. With the chain in place and the wheels on the ground pull the wheel back until the chain is reasonably tight, check to confirm that the tire is centered behind the seat tube, then tighten the axle nuts while holding some pressure against the chain. The chain should not sag.
    Last edited by Al1943; 04-26-11 at 12:43 PM.

  3. #3
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    Thanks for the quick reply! I will try this first thing in the morning and report back in when I succeeded. Or have troubles connecting the gears...

  4. #4
    Constant tinkerer FastJake's Avatar
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    Quote Originally Posted by Al1943 View Post
    The axle should not go to the end of the horizontal dropout.
    This is good, but I disagree with the rest. The chain should not be "tight" when you're finished. It should be as tight as possible without binding at any location. Snug the bolts to tighten the wheel, then slowly spin the pedals to make sure it's not binding. You can feel when it gets tight. Move the wheel a little closer to the frame until it feels smooth at every point. It may sag a little, but it should not be loose and floppy.
    Why "derailer" is the correct way to spell the gear-change mechanism: sheldonbrown.com/derailer.html

  5. #5
    Senior Member
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    Quote Originally Posted by FastJake View Post
    This is good, but I disagree with the rest. The chain should not be "tight" when you're finished.
    That's why I said "reasonable tight".

  6. #6
    Senior Member BCRider's Avatar
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    Quote Originally Posted by Al1943 View Post
    That's why I said "reasonable tight".
    Sadly a lot of folks would take that to mean that it should be a little tight. And as we know if it's only a little tight in some spots it can end up a lot tight in others. It's why I sort of follow FastJake's idea but in my own words when I typically say something like "the right tension is just barely no tension at all. And test this in a few spots because the sprockets are seldom totally round. Adjust so it doesn't get actually tight at any point.".
    Model airplanes are cool too!.....

  7. #7
    Constant tinkerer FastJake's Avatar
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    This is written for fixed gear, but the same idea applies to any bike without a chain tensioner/derailer. Sheldon says it best:

    The chain tension on a fixed gear is quite critical, and is regulated by moving the rear axle back and forth in the fork ends. If the chain is too tight, the drive train will bind, perhaps only at one angle of the pedals (chainwheels are not usually perfectly concentric). It should be tight as it can be without binding. If the chain is too loose, it can fall off.

    Notice how freely the drive train turns when the chain is too loose. That is how freely it should turn when you are done, but with as little chain droop as possible.
    Why "derailer" is the correct way to spell the gear-change mechanism: sheldonbrown.com/derailer.html

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