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  1. #1
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    stripped bottom braket

    Well it seems that the nondrive side of b/b shell is stripped. The threads were tapped, but then restripped when I went for the first ride after, basiclly pulled the b/b out of the shell and shredded the threads. I've read several options on ways to continue to use the frame. JB Weld inside the shell, then nonstick spray on the thread of the b/b to allow the shell to be removed once the JB sets. Other option is threadless b/b, which don't seem to come in splined which I would prefer so I can keep using my raceface crank. That being said it is cheaper to get an new crank than a new frame.

    So any ideas, help, suggestions are welcome.

  2. #2
    one chain loop
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    don't you think its a sign to buy a new frame?

    here's an idea: invest on body armor.
    everything sucks but my vacuum cleaner.

  3. #3
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    Get a cheap external bottom bracket style crank set, and bearings.
    Slap them in the striped out bracket with the right number of spacers.
    This design puts little to no workload on the threads.
    There is inward pressure - this should hold up fine.

  4. #4
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    Quote Originally Posted by speeder3800
    Get a cheap external bottom bracket style crank set, and bearings.
    Slap them in the striped out bracket with the right number of spacers.
    This design puts little to no workload on the threads.
    There is inward pressure - this should hold up fine.

    ????????
    Quote Originally Posted by thefuzzbl
    aluminium has a tendency to fail when you need it most. i.e. you end up with a bad day.

  5. #5
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    Quote Originally Posted by speeder3800
    Get a cheap external bottom bracket style crank set, and bearings.
    Slap them in the striped out bracket with the right number of spacers.
    This design puts little to no workload on the threads.
    There is inward pressure - this should hold up fine.
    I'd love to hear more on how this actually works....

  6. #6
    CB2
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    This would likely cost more than a new frame, but I think FSA makes an insert to convert your standard BB shell to the new BB30 with press in bearings. But then you need a new crank too.

  7. #7
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    Would something like this YST Repair Bottom Bracket work for you?


  8. #8
    Yo!
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    You can also see if there's any larger diameter bb cups available and simply rechase the shell to take out the stripped material and create new threads.

    Other than that I would have to agree with fishcreek. See this as an opportunity to get the frame you've had your eye on.

  9. #9
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    Quote Originally Posted by CB2
    This would likely cost more than a new frame, but I think FSA makes an insert to convert your standard BB shell to the new BB30 with press in bearings. But then you need a new crank too.
    FSA's adapter goes the other way, BB30 is larger than a normal BB
    Quote Originally Posted by thefuzzbl
    aluminium has a tendency to fail when you need it most. i.e. you end up with a bad day.

  10. #10
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    Quote Originally Posted by pyze-guy
    Well it seems that the nondrive side of b/b shell is stripped. The threads were tapped, but then restripped when I went for the first ride after, basiclly pulled the b/b out of the shell and shredded the threads. I've read several options on ways to continue to use the frame. JB Weld inside the shell, then nonstick spray on the thread of the b/b to allow the shell to be removed once the JB sets. Other option is threadless b/b, which don't seem to come in splined which I would prefer so I can keep using my raceface crank. That being said it is cheaper to get an new crank than a new frame.

    So any ideas, help, suggestions are welcome.
    OK, here are my suggestions. If the frame in question is less than $500, just get a new one. BTW, what material is the frame made of? If it is steel, I'm sure a good framebuilder can weld a new BB shell onto the frame, but then it has to be repainted. My guess is this will cost $300 to $400. Maybe upgrade to an EBB while you are at it? If you have a high-end or custom steel or Ti frame, this may be worth it.

    Othrewise, the BB shown above by Ruppster would worth, but you will need a square taper crank to go with it, maybe a nice ENO crank?

    Another kind of off-the-wall solution would be a Schlumpf 2 speed gearbox. It does not use the BB threads to mount. But then I guess your bike won't be a Singlespeed anymore!

    Mark

  11. #11
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    I just bought a house so buying another bike is out of the question.

    I JB Welded the loose cub in the shell. If that doesn't hold I have the YST b/b ordered and will use it. There is a local builder who will rebuild the threads for $120, but the frame is a SoulCycles Hooligan I picked for $100 on c-list (at least that what I was told, it has the headbadge and stickers that say soulcycles, but looks to me to be a Fetish Fixation) and I have another s/s mtb frame I can use if needed, so I doubt I would go that route.

  12. #12
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    Originally Posted by speeder3800
    Get a cheap external bottom bracket style crank set, and bearings.
    Slap them in the striped out bracket with the right number of spacers.
    This design puts little to no workload on the threads.
    There is inward pressure - this should hold up fine.

    Quote Originally Posted by larsbaby
    I'd love to hear more on how this actually works....
    Indeed, speeder3800 is quite right. Any external 3 piece BB will work just fine without threads holding in the cups. External bottom brackets are held together by way of the left crank arm attaching to the right crank axle. Shimano actually has a threadless external BB , but even without the full length housing, it will hold together and work fine.
    Just one more rep and I get the toaster!

  13. #13
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    Quote Originally Posted by aka brad
    Indeed, speeder3800 is quite right. Any external 3 piece BB will work just fine without threads holding in the cups. External bottom brackets are held together by way of the left crank arm attaching to the right crank axle. Shimano actually has a threadless external BB , but even without the full length housing, it will hold together and work fine.
    but that requires a machined tolerance for the bearings to press into, a stripped out threaded bb is not the same. So an ovalized headtube will hold a headset tight as well?

    that shimano threadless bb works in the same way a headset works, if a headtube is machined slightly oversized it will never work right, the same goes with a bb shell that has been stripped out

    any rider torque will cause creaking and further damage to the frame.
    The cup has no support except for the threaded portion, With the Shimano BB92 the bearing are supported by frame.

    if you don't believe me go out and loosen your external bb cups a 1/4 turn and see how much slop you have

    that YST repair BB is pretty much the only option.
    Quote Originally Posted by thefuzzbl
    aluminium has a tendency to fail when you need it most. i.e. you end up with a bad day.

  14. #14
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    Quote Originally Posted by scooter916
    but that requires a machined tolerance for the bearings to press into, a stripped out threaded bb is not the same. So an ovalized headtube will hold a headset tight as well?

    that shimano threadless bb works in the same way a headset works, if a headtube is machined slightly oversized it will never work right, the same goes with a bb shell that has been stripped out

    any rider torque will cause creaking and further damage to the frame.
    The cup has no support except for the threaded portion, With the Shimano BB92 the bearing are supported by frame.

    if you don't believe me go out and loosen your external bb cups a 1/4 turn and see how much slop you have

    that YST repair BB is pretty much the only option.
    I will not debate that it is the best solution, but it has a very good chance of working. The remaining threads in the BB shell need only hold the cups laterally, while the crank and axle will hold it together. But comparing the stresses on crank bearings to headset bearings is apples to monster trucks. The torque on a headset is from a 2 1/2 foot lever on the bottom called a fork and wheel and two opposing 14" levers on the top called a handlebar. The BB levers are 180mm maximum on each side. I then turned the negative to positive and positive to negative.. It.....Could....Work!
    Just one more rep and I get the toaster!

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