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  1. #1
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    Reputation: drpcken's Avatar
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    Need help with Mongoose crankset/BB replacement

    I have a Mongoose DXR-AL (model# R4504WMFT).

    It was my womans and she didn't ride it so me and my riding buddy have almost completely replaced all the factory parts (she rides GREAT now). The only things left that are factory is the frame and the Crankset/BB.

    So I'm getting ready to order a Shimano LX crankset to add to it, but I have no idea the Spindel Length or BB Shell Width. I called Mongoose and they couldn't tell me anything! All they knew were the number of teeth (42-34-24) and the 3-L (not sure what that means) which is 116mm.

    Neither I nor my buddy have ever done a crankset replacement so we are kind of in the dark. I don't want to buy a crankset and then turn out its the wrong one.

    Does anyone have any suggestions or can guide me in the right direction?

    Thanks!!

  2. #2
    Endo Gold Medalist
    Reputation: Luke Trailrider's Avatar
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    My BB's are huge. Like the size of golf balls.

  3. #3
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    ^ said riding buddy

  4. #4
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    Not sure what model that is exactly but

    If you remove the bottom bracket and look closely, it should have the shell size, 68 or 73 written on it. The spindle size is probably on there too but more importantly, get the shell size right.

    The LX cranks with the splined BB should come with pretty much a set spindle size these days or maybe two size options. This will determine the "chain line" (how off set your crank rings are compared to the rear cassette). Unfortunately, without much frame info, you'll have to buy the right shell size and guess at the spindle length if there's more than 1 length offered for the LX. Chainline will determine how well your bike shifts up front and how much chain will bind but bike should still be rideable. (many people on this board may hate me for that last statement). But the cranks will fit regardless, you just have to figure out the spindle length/chain line.

    hope that helps.

    REEK

  5. #5
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    Hey thanks for the info! I pulled the crank off this morning and did some measuring.

    The actuall BB (also called spindel right?) is 120mm (minus the threads). The shell size is 68mm.
    The crank is 170mm in length.

    I'm still looking for a good quality shimano part to match this. Do these numbers sound right?

  6. #6
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    ok i think i'm ready to buy my new crankset/bb

    if i buy them together it sholdn't be a problem, but if i buy the BB seperate from the crankset, how will I know which is compatible with which? I plan on buying shimano parts.

  7. #7
    mtbr member
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    Ok I'm thinking of getting this bracket
    http://xoomgear.com/mountainbike/bot...t-BB-ES50/658/

    and picking a LX crank to go with it. Would that make sense?

    Thanks for all the help!

  8. #8
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  9. #9
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    nevermind, that bracket got horrible reviews

  10. #10
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    unfortunately

    you're stuck with the shimano BB if you use a shimano crank. You could look into FSA and Truvativ. They sell moderate priced cranks with ISIS BB's that lets you have a bit more freedom with bottom bracket (BB) choices.

    I'm still using "old" square tapered bottom bracket/cranks and XTR splined BB/crank set ups. Not overly impressed with ISIS to change everything over yet even though that stuffs been out for a while.

    REEK

  11. #11
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    Reputation: Luke Trailrider's Avatar
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    Quote Originally Posted by Reek
    you're stuck with the shimano BB if you use a shimano crank. You could look into FSA and Truvativ. They sell moderate priced cranks with ISIS BB's that lets you have a bit more freedom with bottom bracket (BB) choices.

    I'm still using "old" square tapered bottom bracket/cranks and XTR splined BB/crank set ups. Not overly impressed with ISIS to change everything over yet even though that stuffs been out for a while.

    REEK
    Thanks for clearing these things up for us. Here is a good pic you could make into your avatar to match your quote to show our appriciation.

  12. #12
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    I know its probably an over kill, but I went with the Bontrager Race Lite GXP

    Just waiting for it to come in

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