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  1. #1
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    Problems installing new chainrings

    Hi,

    I'm trying to install a new set of chainrings on my Schwinn Homegrown. It has a triple set of 58/94 BCD size, as best I can tell.

    Using the crank puller, I was able to get the crank off and pull off the old chainrings. However, I am running into a problem. The old inner chainring (granny?) bolted into the middle chainring. The new middle chainring has no inner bolt circle. Therefore, there is no place to attach the inner chainring.

    A book I have mentions that the granny ring should bolt directly into the crank arm (spider?) Does this mean that I have to buy a new crank arm?

    So basically, I need some basic info on cranks/chainrings. Here are the questions I need answered:

    1) Do crank arms come with and without an inner set of bolt holes?

    2) How much do crank arms cost?

    3) Am I missing something? Is there another way to attach the granny ring even though neither the middle chainring nor the spider has an inner bolt circle?

    4) What should I do????


    Thanks for all the help!
    Micah

  2. #2
    Senior Member sydney's Avatar
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    Quote Originally Posted by MicahWedemeyer
    Hi,

    I'm trying to install a new set of chainrings on my Schwinn Homegrown. It has a triple set of 58/94 BCD size, as best I can tell.

    Using the crank puller, I was able to get the crank off and pull off the old chainrings. However, I am running into a problem. The old inner chainring (granny?) bolted into the middle chainring. The new middle chainring has no inner bolt circle. Therefore, there is no place to attach the inner chainring.

    A book I have mentions that the granny ring should bolt directly into the crank arm (spider?) Does this mean that I have to buy a new crank arm?

    So basically, I need some basic info on cranks/chainrings. Here are the questions I need answered:

    1) Do crank arms come with and without an inner set of bolt holes?

    2) How much do crank arms cost?

    3) Am I missing something? Is there another way to attach the granny ring even though neither the middle chainring nor the spider has an inner bolt circle?

    4) What should I do????


    Thanks for all the help!
    Micah
    Some grannys bolt to the middle ring. Simple enough.

  3. #3
    feros ferio John E's Avatar
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    There are at least three ways to assemble a triple:
    1) (most common): the two outer rings bolt to the spider and the inner bolts to a smaller BCD set of holes on the inside of the spider. This is the system for which your new chainrings are designed.
    2) (triplizer; your old setup): the two outer rings bolt to the spider and the inner bolts to a second row of holes in the middle ring. If you want to retain this system, you will need a new middle ring which has the second set of holes, as your old one did. Harris Cyclery or LooseScrews may have what you need.
    3) (least common, smallest range): all three rings bolt onto a single set of holes in the spider, using long stack bolts and spacers.

    If you want to go with the first option, you will need a new right crank. The second option will require you to exchange that new middle ring for a triplizer ring. The third option will require you to accept a larger grannie and buy a set of long stack bolts, assuming you can find them. They are pretty rare.
    "Early to bed, early to rise. Work like hell, and advertise." -- George Stahlman
    Capo [dschaw'-poe]: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger, S/N 42624
    Peugeot: 1970 UO-8, S/N 0010468
    Bianchi: 1981 Campione d'Italia, S/N 1.M9914
    Schwinn: 1988 Project KOM-10, S/N F804069

  4. #4
    Junior Member
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    Thanks John, that's exactly the kind of answer I needed!

  5. #5
    Junior Member
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    I found the following right crank at LooseScrews:
    http://www.loosescrews.com/index.cgi...id=43953369607

    My only question about it is this: The crank is listed as a 95/58 BCD. Can this be correct? I thought that the standard compact crank BCD is 94/58.

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