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Thread: Bottom Bracket

  1. #1
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    Bottom Bracket

    How do I tell which BB I have on my bike?

    2009 Trek Fuel EX7

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  3. #3
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    You have a Holowtech II external bearing BB

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    oh sorry, I meant how do I tell if its bb30, 68mm, 70mm, etc, etc, short of pulling it apart and measuring it?

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    Quote Originally Posted by nov0798
    oh sorry, I meant how do I tell if its bb30, 68mm, 70mm, etc, etc, short of pulling it apart and measuring it?
    You "look" at it

    Post a picture

    You have a Holowtech II external bearing BB
    and most likely 68mm at a guess
    Duct tape iz like teh Force. It has a Lite side and a Dark side and it holdz the Universe together.

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    Well I have looked at it, and short of pulling it apart I thought maybe someone knew off the top of their head, since it doesnt have size listed on it, which was the reason for the 2nd post! Just says DO NOT DISASSEMBLE!

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    Quote Originally Posted by nov0798
    oh sorry, I meant how do I tell if its bb30, 68mm, 70mm, etc, etc, short of pulling it apart and measuring it?
    Turn your bike upside down and measure across the bb shell. It's likely 68 or 73mm. Doesn't really matter since those bb's come with spacers for both sizes.

    Check the sticky thread: Outboard Bearing Bottom Bracket Service Guide. With Pics.

  8. #8
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    Quote Originally Posted by nov0798
    How do I tell which BB I have on my bike?

    2009 Trek Fuel EX7
    The Stock crankset and bottom bracket for the 09 EX7 was a Shimano FMC-532 Deore Hollow Tech II external bearing system. The bottom bracket consists of two bearing cups that thread into the bottom bracket shell of the frame. This type of bottom bracket is adjustable for use with either a 68 or 73mm bb shell through the use of spacers. You EX 7 has a 73mm bottom bracket shell, and so any crankset of this type that you get or use should be set up accordingly. The "Do not disassemble" warning on the cups is in reference to removing the bearings from the cups. You can remove the cups from the bike easily with the proper tools. It should also be noted that you can disassemble the bearings from the cups and replace them as well, regardless of the warning. But it requires the proper tools and know how to do so without damaging the cup or the new bearings.

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