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  1. #1
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    Question for Ibis about BB shells

    Hi,

    I'm just wondering why you use press fit BB's on the ripley and sl-r but went back to threaded for the HDR.

    Personally I prefer threaded, it's part of the reason I bought an HDR. I'm "threaded for life" because I fear creaking ( I have avoided all eccentric BB's for this reason ) and I work on my own bikes. I'd much rather have to service a threaded BB.




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  2. #2
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    Question for Ibis about BB shells

    I agree. I get the supposed benefits of press-fit, but I own the tools and the BBs for threaded and feel like press-fit is one of those movements that's really about ease of manufacture over real utility. I'm also sort of terrified of f*cking up the fit and having a jacked $$$ frame.

    My guess is that the HD & HDR molds are close enough that a press-fit BB change would have been enough of a PITA to implement that they just left it threaded.


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  3. #3
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    I'm with both of you as well. Zero interest in a PF BB frame, thats the main reason why I kept my SL and will not buy an SLR or Ripley.

  4. #4
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    In theory transferring external bb cranking forces into the frame via a threaded interface is a bad idea. In practice it is too. External BBs also forces a wider 'Q' factor.

    What I'd be interested in understanding is why the small legacy bearings and crank axle dimensions were retained rather than going to 30mm inside diameter press fits.

  5. #5
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    Quote Originally Posted by Mark2c View Post
    In theory transferring external bb cranking forces into the frame via a threaded interface is a bad idea. In practice it is too. External BBs also forces a wider 'Q' factor.
    Care to tell us non-engineer types who have been using threaded BBís without problems or issues for decades why itís a bad idea?

  6. #6
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    Good to hear they work for you.

    Round here (NZ) they creak, corrode, work loose, rust, get dented and are a general PITA. People cross thread them. They are too wide (Q-factor) and are less still than they would be inboard.

    Bigger bearings, inboard with better seals and narrower should be better. Pity BB-92 isn't that.

    My memory is that external BBs have only been widely used for about 9 years...
    Last edited by Mark2c; 06-15-2014 at 01:39 AM.

  7. #7
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    Question for Ibis about BB shells

    9 years sounds about right. Maybe I'll get me some middle burn cranks and a Phil Wood BB. Square taper baby!


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  8. #8
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    Question for Ibis about BB shells

    The Idea that outboard bearings necessarily produce higher q makes no sense to me. Q mostly depends on your crank design and chainstay width. Look at road cranks where you have cranks that use outboard bearings and yet have a q in the 140s.

    In any event, lower q isn't better for everyone.

  9. #9
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    I'll stick with cotter pin cranks...

  10. #10
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    Quote Originally Posted by D_Man View Post
    The Idea that outboard bearings necessarily produce higher q makes no sense to me.
    This. Rear hub size dictates the Q factor. Ask the DH and fat bike guys.

  11. #11
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    anyone use the new wheel mfg bb sleeves? I have one for a bb86/92 crank that would fit my ripley, but need a sram/shimano crank to test it out. Looks like this:

    Wheels Mfg BB86/92 Bottom Bracket w/Angular Contact Bearings for 24mm (Shimano) Cranks

    Any thoughts?

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