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  1. #1
    Fiend
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    Biopace SG cranks.

    I just picked up a Schwinn Woodlands with Biopace SG cranks on it. I'm cannibalizing it for parts. When I went to remove the cranks, I discovered that they were bolts instead of nuts, and I couldn't get my Park crank removal tool to work. I didn't force it, though. The threads fit. Does this require a special tool, or do I just need to give it some WD40 or other stuff and push harder?
    Code:
       __o     It doesn't matter what you ride, 
     _ \<,_    only that you ride.
    (_)/ (_)

  2. #2
    Gone, but not forgotten Sheldon Brown's Avatar
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    Quote Originally Posted by Altinos
    I just picked up a Schwinn Woodlands with Biopace SG cranks on it. I'm cannibalizing it for parts. When I went to remove the cranks, I discovered that they were bolts instead of nuts, and I couldn't get my Park crank removal tool to work. I didn't force it, though. The threads fit. Does this require a special tool, or do I just need to give it some WD40 or other stuff and push harder?
    Most better quality bottom brackets use bolts, not nuts. On older ones, they often needed a 15 mm socket, newer ones used a 14 mm socket. More recent stuff uses an 8 mm Allen wrench.

    The bolts are generally all interchangeable.

    By the way, there's no such thing as a "Biopace crank." It's the chainrings that are Biopace.

    See: http://sheldonbrown.com/biopace

    Sheldon "Bolts" Brown
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  3. #3
    Fiend
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    Quote Originally Posted by Sheldon Brown
    Most better quality bottom brackets use bolts, not nuts. On older ones, they often needed a 15 mm socket, newer ones used a 14 mm socket. More recent stuff uses an 8 mm Allen wrench.

    The bolts are generally all interchangeable.

    By the way, there's no such thing as a "Biopace crank." It's the chainrings that are Biopace.

    See: http://sheldonbrown.com/biopace

    Sheldon "Bolts" Brown
    I say Biopace crank because it doesn't appear that I can remove the chainrings from the crank, looks like they're riveted.

    The crankarms are also plastic, which is something I'm not used to. I was able to get the bolts off with a 14mm socket.
    Code:
       __o     It doesn't matter what you ride, 
     _ \<,_    only that you ride.
    (_)/ (_)

  4. #4
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    Make sure that the washer is removed along with the bolt.

  5. #5
    surly old man jgedwa's Avatar
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    Quote Originally Posted by Altinos
    The crankarms are also plastic.
    !!!!!!

    Hope not

  6. #6
    me have long head tube TallRider's Avatar
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    The crankarms are metal (probably steel) with a plastic cover. This is probably what you're looking at:

    I got this crank off of an old Diamondback mtb, and then used it on this build for a friend.

    Anyway, cheaper bottom bracket spindles had threads sticking out of the end, and used a nut to tighten the crank onto the BB spindle, instead of having a hole for a bolt to do the job instead, as do most (and all better) bottom brackets.

    However, your standard crank remover tool will work on this sort of bottom bracket as well.

  7. #7
    Scott n4zou's Avatar
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    Quote Originally Posted by Altinos
    I say Biopace crank because it doesn't appear that I can remove the chainrings from the crank, looks like they're riveted.
    Correct.
    Quote Originally Posted by Altinos
    The crankarms are also plastic, which is something I'm not used to. I was able to get the bolts off with a 14mm socket.
    Plastic coating over Alloy. The aluminum/magnesium alloy used is very prone to corrosion. Be careful not to scratch or puncture that plastic coating. Doing that will not damage it but it will start looking really ugly when exposed to air. It's sort of like rust on steel.

  8. #8
    me have long head tube TallRider's Avatar
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    Quote Originally Posted by n4zou
    Plastic coating over Alloy. The aluminum/magnesium alloy used is very prone to corrosion. Be careful not to scratch or puncture that plastic coating. Doing that will not damage it but it will start looking really ugly when exposed to air. It's sort of like rust on steel.
    If he's got the cranks that I had (pictured above), then it's steel underneath the plastic - it attracted a magnet pretty obviously.
    I don't see any reason that they would use an aluminum/magnesium alloy on a low-end crank.
    What cranks did they do this with, and when? I'm curious.

  9. #9
    Fiend
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    Quote Originally Posted by Noam Zane
    Make sure that the washer is removed along with the bolt.
    D'oh! That was it. Thanks!
    Code:
       __o     It doesn't matter what you ride, 
     _ \<,_    only that you ride.
    (_)/ (_)

  10. #10
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    Quote Originally Posted by jgedwa
    !!!!!!

    Hope not
    Yes, they do appear to be plastic coated metal.
    Code:
       __o     It doesn't matter what you ride, 
     _ \<,_    only that you ride.
    (_)/ (_)

  11. #11
    Scott n4zou's Avatar
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    Quote Originally Posted by timcupery
    If he's got the cranks that I had (pictured above), then it's steel underneath the plastic - it attracted a magnet pretty obviously.
    I don't see any reason that they would use an aluminum/magnesium alloy on a low-end crank.
    What cranks did they do this with, and when? I'm curious.
    Alloy from recycled engine and transmission blocks. If the manufacturer uses recycled material for the production of parts where a good finish is required the parts will be painted with a high quality epoxy paint, power coated, or lowest cost option dip coated in plastic. They also plastic coat steel to hid it's use.

  12. #12
    Senior Member robo's Avatar
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    Cranks that look like that that i've seen have always been steel encased in plastic. I imagine if they were alloy with an additional plastic casing, they would be somewhat bulkier anyway.

  13. #13
    The good looking one Bikehead's Avatar
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    Hello All:

    I have two Schwinn Woodlands, that I have made
    fowl weather commuters out of them. They are great,
    for snow, rain. I had to replace the crank on one,after it
    fell over and bent the chainwheel. I used a Nasbar triple
    crank, it just bolted right on to the bottom braket. I
    belive it was about $25. I have had the one bike since it
    was new in 1991. Someone gave me the other one.I added
    fenders, rack and lights, and use it in the winter,and on wet days.
    It is a good soild bike,and will not let you down.
    Just don't drop it on the chainwheels that aren't the strongest.
    Hope you enjoy your Woodlands.
    Bikehead
    1993 Schwinn Paramount series 3
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  14. #14
    me have long head tube TallRider's Avatar
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    Quote Originally Posted by n4zou
    Alloy from recycled engine and transmission blocks. If the manufacturer uses recycled material for the production of parts where a good finish is required the parts will be painted with a high quality epoxy paint, power coated, or lowest cost option dip coated in plastic. They also plastic coat steel to hid it's use.
    Interesting, that makes sense. Thanks.

    Quote Originally Posted by robo
    Cranks that look like that that i've seen have always been steel encased in plastic. I imagine if they were alloy with an additional plastic casing, they would be somewhat bulkier anyway.
    Good point - although old-school aluminum cranks were pretty svelte (and probably flexy). See this picture (what's not on my fixie). But those were still thicker profile (as viewed from above) than steel underneath the plastic in your cranks would be, so point stands.

  15. #15
    Fiend
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    Quote Originally Posted by timcupery
    If he's got the cranks that I had (pictured above), then it's steel underneath the plastic - it attracted a magnet pretty obviously.
    I don't see any reason that they would use an aluminum/magnesium alloy on a low-end crank.
    What cranks did they do this with, and when? I'm curious.
    Those are the exact cranks I have.
    Code:
       __o     It doesn't matter what you ride, 
     _ \<,_    only that you ride.
    (_)/ (_)

  16. #16
    Fiend
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    Quote Originally Posted by Bikehead
    Hello All:

    I have two Schwinn Woodlands, that I have made
    fowl weather commuters out of them. They are great,
    for snow, rain. I had to replace the crank on one,after it
    fell over and bent the chainwheel. I used a Nasbar triple
    crank, it just bolted right on to the bottom braket. I
    belive it was about $25. I have had the one bike since it
    was new in 1991. Someone gave me the other one.I added
    fenders, rack and lights, and use it in the winter,and on wet days.
    It is a good soild bike,and will not let you down.
    Just don't drop it on the chainwheels that aren't the strongest.
    Hope you enjoy your Woodlands.
    I needed the parts for a Nashbar MTB frame that I just got in my size. The Woodlands is a woman's frame and far too small for me, although the cranks were 170mm. I'm just taking the parts off and will probably sell the frame.
    Code:
       __o     It doesn't matter what you ride, 
     _ \<,_    only that you ride.
    (_)/ (_)

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