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Thread: Sizing a BB?

  1. #1
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    Sizing a BB?

    I have a 92'/93' trek 2300 and I am trying to figure out the size of the bb. Any tips?

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    Remove it. Everything will be on a label. If not, then you can measure it easily. bk

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    Newbie pedalhead110's Avatar
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    If there is no label on the current bb, you'll need to measure the bb shell and the length of the spindle with a pair of calpers.

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    Elitist Troglodyte DMF's Avatar
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    Or tell us what components are on the bike so we wouldn't be making a WAG...

    New Posters - please READ THIS
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    I have senior moments... bikinfool's Avatar
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    Probably a 600 double crankset on there, using a 68 x 113....probably. Would help to know crank that's on there and what chainline it has for a better guess.
    suum quique
    Mountain bikes: Santa Cruz Hecklers (99, 02, 07), Santa Cruz Nomad, Moots YBB, Trek OCLV Pro Issue, American Breezer
    Road bikes: TST, Trek 2300 (Carbon/Alum)

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    The frame's bottom bracket shell is 68 mm wide and English threaded. So, you need an English threaded 68 mm bottom bracket. The spindle length you need will depend on the crank you have or substitute.

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    Thanks for posting a link, but the reason I am asking is because the frame has nbo current BB or crankset. Otherwise I would have just read the measurements on the current on. Man this is a tough crowd.

    Thanks Hillrider!!!

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    Quote Originally Posted by 143gadgets View Post
    Thanks for posting a link, but the reason I am asking is because the frame has nbo current BB or crankset. Otherwise I would have just read the measurements on the current on. Man this is a tough crowd.

    Thanks Hillrider!!!
    That is critical information to have...
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

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    Quote Originally Posted by 143gadgets View Post
    Thanks for posting a link, but the reason I am asking is because the frame has nbo current BB or crankset. Otherwise I would have just read the measurements on the current on. Man this is a tough crowd.

    Thanks Hillrider!!!
    The spindle length will depend on the crankset you buy for it. The BB housing is 68mm.

  10. #10
    I have senior moments... bikinfool's Avatar
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    Quote Originally Posted by 143gadgets View Post
    Thanks for posting a link, but the reason I am asking is because the frame has nbo current BB or crankset. Otherwise I would have just read the measurements on the current on. Man this is a tough crowd.

    Thanks Hillrider!!!
    It's not that it's a tough crowd more than you made a common misassumption, i.e. that the bottom bracket is specific to the bike, whereas it's mostly about the crank. It's not easy to determine a spindle length with a crank/bb already installed, so everyone assumed with the named bike the crank/bb were installed. Tough would have been to say get a frikkin' ruler...
    suum quique
    Mountain bikes: Santa Cruz Hecklers (99, 02, 07), Santa Cruz Nomad, Moots YBB, Trek OCLV Pro Issue, American Breezer
    Road bikes: TST, Trek 2300 (Carbon/Alum)

  11. #11
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    Quote Originally Posted by 143gadgets View Post
    Man this is a tough crowd.
    We tend to take things at face value here. If we had to read into every question and decide what the poster probably was asking, we'd waste even more time on this forum than we already do.

    You said you in your OP that you had a Trek 2300. I, and most everyone else, assumes that you mean a complete bike which means you have a crankset too. If you had said you had a Trek 2300 bare frame or a Trek 2300 w/o a crankset or BB, you'd have received different replies. You also could have done a little searching, found a crankset you liked, then asked if it would fit. Again, you would have received different replies.

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