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  1. #1
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    shimano plastic BB cup cracked wtef?!

    what should I do? get a replacement? return it? I bought it 5 days ago and it recently cracked. i knew that was going to happen.

  2. #2
    Senior Member skilsaw's Avatar
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    wtef is spelled wtf. If a plastic bb cup cracks, it is a sign that the bicycle frame is faulty. The only thing you can do is purchase a new bike.
    The one who has the most bikes wins.

  3. #3
    coprolite fietsbob's Avatar
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    the left side and the rest of cartridge shimano BB's are steel , there are aluminum replacements for the right side.
    aftermarket.
    But really It just stabilizes the sleeve of the assembly..
    perhaps you overtightened it when you put it in.?

  4. #4
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    Did you put Loctite on it by chance?

  5. #5
    Senior Member surreal's Avatar
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    the preponderance of plastic BB cups makes me queasy. Here're some musings on the subject:

    -Get an all-metal BB set next time. Some of em are dirt-cheap. All the new shimano square taper BB sets seem to be plastic on the left side, which is sad.
    -make sure you don't overtighten or cross-thread the bb cup, regardless of material
    -someone mentioned loctite. This stuff could end up effing with the plastic.
    -if you're BB is exceedingly difficult to install, you may want to get the shell re-tapped.

    -rob

  6. #6
    Fred-ish rogerstg's Avatar
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    It was overtightened when installed. It should not be a problem even if cracked if it stays firmly in the bottom bracket. It functions as a round shim/support on the left side. Shimano used to make an aluminium replacement, but I have not been able to find those for some time.

  7. #7
    afraid of whales Mr IGH's Avatar
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    I've run Shimano's plastic cup for three winters, hasn't cracked yet, sounds like it was overtightened.

  8. #8
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    that maybe the case. Should I just return it and stick with loose BB? I like it better because it gives you peice of mind that its full metal. Or should I go with the superior design of seal cartridge? i already asked for a new cup and i'll see if i can install this one correctly.

  9. #9
    Low car diet JiveTurkey's Avatar
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    It'll work just fine if it is cracked.
    Quote Originally Posted by slopvehicle View Post
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  10. #10
    Senior Member vredstein's Avatar
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    Got one for you

    Quote Originally Posted by CarLo View Post
    what should I do? get a replacement? return it? I bought it 5 days ago and it recently cracked. i knew that was going to happen.
    PM me with your address and I'll send you a NOS alloy replacement. Not sure on the absolute standards, but it's 21.5 mm long and about 34.7 mm outside diameter.
    Attached Images Attached Images
    "See, it's not that getting wet is a big deal. Really, it's what you're getting wet with.
    Fenders....because it's probably urine."
    Bike Snob NYC

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