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  1. #1
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    New question here. Looking for Crank Help

    I have a Trek 4500 and I need to replace the crank arms. I put new pedals on it last year and when I took them off the threads were stripped. (How does that happen??). Anyway, When I'm buying cranks what sizes am I looking for to make sure the new cranks fit on my bike? I have no idea that the BB size is or the arm length although, I presume the length is 175mm.

    Aren't the factory cranks on there Tru-Vativ or something?

    Anyway thanks in advance,

    Homefish

  2. #2
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    You might be able to find new crank arms. If they are Truvativ, look here at AE Bike. But it might end up being cheaper to find a new crankset though. E.g. consider this deal from Pricepoint: Race Face Ride XC Crankset. (That's just one example. Look around at other stores before buying.)

  3. #3
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    OK Cool, thanks for the reply! So pretty much any size will fit? They are mostly standard?

    Homefish

  4. #4
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    Standard will be a 175mm crank length. Your bottom bracket is 73mm if I remember correctly. What year model is your 4500? The Trek archives can tell you what cranks are on it. Current model run Shimano. I'd definitely look at an exterior bearing bottome bracket if you upgrade the whole crankset.

  5. #5
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    Not looking to upgrade, just need to replace. It's last years 4500, the army green and black one. I thought I tried looking on Trek's site for info on the crank but I don't remember coming up with anything. I'll try again when I get to work. Does the tooth size matter? I hate adjusting the dérailleur, I can never get it right. What I'm worried about is the cranks fitting on the existing BB. Do I need to be worrying about that?

    I guess what I want to hear is, as long as I buy 175mm (or what ever length arm I want) most cranks will fit on the existing BB. But I should try and match teeth on the sprocket. Am i silly or close to correct?

    Homefish

  6. #6
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    I did some looking...your bottom bracket looks like this, right?



    If so, you need to look for a crankset without a BB that fits square taper BBs. You can probably find a million on ebay. 175mm crankarm is what came on your bike, I'm sure. The chainrings are going to be 44-32-22T so that's pretty much the standard across the board.

    This is at least comparable to what came on your bike:
    http://www.jensonusa.com/store/produ...Crank+Set.aspx

    Just make sure to select the square taper option if that's what you have.

  7. #7
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    Cool thanks for the help!! I don't remember seeing my bottom bracket but I'm sure it is.

    Homefish
    Last edited by Homefish; 08-21-2009 at 08:04 AM.

  8. #8
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    Quote Originally Posted by Homefish
    Cool thanks for the help!! I don't remember seeing my bottom bracket but I'm sure it is.
    Before you order anything make sure the ends that the cranks attach to look like this or you'll need to order a different set of cranks.

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