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  1. #1
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    What good are Integrated Bottom Brackets?

    Well hey, if we can have one for headsets, why not BB's?

    Especially considering I just got my shipment of XTR Integrateds in. No thanks to the usless plebs at Shimano Australia who "Knew about them, but wasn't sure if, when or how much".

    Now the press fit sections are 41.04mm and the whole thing is some kind of composite/nylon, which I must say doesn't scream 'durability'. There's also on the literature a 'do not re-use' clause.

    Pete, Sean, anyone else - how are yours looking after some saddle-time? Are we looking at a throw-away item here?
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  2. #2
    pvd
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    Mine are still fine. No issues yet, but I expect they will have the same contamination issues that the outboards have.

    I'm going to be making my own BB for the Shimano system. Should be a major improvemnt. I've got it all designed in my head. I've even got the stock and all the parts. What I don't have right now is time or spirit. Obviously, I'm a bit busy with a lot of stuff. Plus work.

  3. #3
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    My I.P.V.D. says they're a JOKE! Lame, pathetic, and stupid.

    The rest of me thinks there isn't much of a downside, but also very little upside. External threaded works great, just needing custom 2.5 mm alloy spacers to replace the cruddy plastic ones.

    Anybody done stiffness calculations on an oversized BB shell?


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  4. #4
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    I'm with Steve...

    I'm not a huge fan of change for the sake of change. I like threaded BB shells, and I don't see any particular weight/stiffness/building/using advantage.

    Then again I still use square taper BB's on some of my bikes, so I'm probably just being difficult for the sake of retro-spite.

    -Walt


    Quote Originally Posted by D.F.L.
    My I.P.V.D. says they're a JOKE! Lame, pathetic, and stupid.

    The rest of me thinks there isn't much of a downside, but also very little upside. External threaded works great, just needing custom 2.5 mm alloy spacers to replace the cruddy plastic ones.

    Anybody done stiffness calculations on an oversized BB shell?


    Me neither...
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  5. #5
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    Quote Originally Posted by D.F.L.
    ust needing custom 2.5 mm alloy spacers to replace the cruddy plastic ones.
    The CK ones have alloy spacers. The cup install tool leaves them pristine once installed too, not a scratch on the cups.

    I still like PVD's shell from a tire clearance perspective and I'd think it would have to be stiffer having the stays stuck an extra half inch to either side.

  6. #6
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    Yeah but they look sexy. (not mine)

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  7. #7
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    Quote Originally Posted by jay_ntwr
    ... and I'd think it would have to be stiffer having the stays stuck an extra half inch to either side.
    Good luck spacing the drive-side stay out any further. THAT'S the problem with these BBs. they don't really improve clearance. They're meant for gigantic carbon tubes, and we're falling all over ourselves to adapt them to steel.

    Bah, Humbug!

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  8. #8
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    i remember seeing some older bikes that had press in bbs and was not impressed with their longevity. granted, the bikes were from a time when proprietary stuff was 'cool' and companies didn't put a whole lot of forethought into design, but they seemed to get loose and creak after the bb was changed out once or twice.

    will the newer cranks' ability to preload the bearings be able to stop creaking do the wear caused by pressing in and taking out the bb cups?

    or maybe those old kleins (?) weren't popular enough so nobody knows what im talking about...

  9. #9
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    With a plate yoke on the drive-side and unsquished 22.2 stays I can get over 80mm of (theoretical) tyre clearance with the 92mm BB. If you used oval stays you could get 85+.

    It allows you to space the non-drive side chainstay further outboard, so at least you get more clearance on one side, right? Add some jiggery-pokery on the drive side and you're all set for 2.5 tyres.
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  10. #10
    pvd
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    I've built and ridden both. I'll take integrated over threaded any day. By integrated I mean Shimano HT2 not BB30. BB30 has no true advantages other than minimizing crank width.

    Structurally, HT2 allows for a stiffer, stronger rear end with less complexity and no weight increase. The chainstays are spread farther apart at the BB requiring less bending. The increased radius of the BB allows the chainstays and DT to meet it farther from the center line placing the spindle within the frame more increasing it's support. Also the curvature of the miters are reduced creating a much stronger joint.

    For FS bikes, they allow more width for mounting pivot for increased stiffness and support with less structure. The bearings can then be spread farther apart decreasing their loads and increasing their lives.

    For carbon bikies, a full carbon shell can be used (no alloy insert). This means lighter cheaper carbon bikes with greater strength.

    I worked at Fat City Cycles when we converted from press in bearings to threaded. I belive that the press in's of that era had problems due to the direct metal to metal interface in the highest stressed most contaminated parts of the bike. The reinforced nylon sleeve of the HT2 BBs solves this problem and has much better sealing. In effect, they should be no different that outboard systems with regard to longevity.

  11. #11
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    Quote Originally Posted by Walt
    I'm not a huge fan of change for the sake of change. I like threaded BB shells, and I don't see any particular weight/stiffness/building/using advantage.

    Then again I still use square taper BB's on some of my bikes, so I'm probably just being difficult for the sake of retro-spite.

    -Walt

    Hah! All the stuff you rail against on your site, and your still running square taper! Hilarious.

  12. #12
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    What's wrong with square taper?

    I mean, I can put out some power, and I've never noticed any flex in the drive system. I literally can't tell the difference between the latest thing and my old UN71.

    Then again, they don't *make* the UN71 anymore... and I like the new stuff too.

    -Walt

    Quote Originally Posted by Schmitty
    Hah! All the stuff you rail against on your site, and your still running square taper! Hilarious.
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  13. #13
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    Quote Originally Posted by Walt
    I mean, I can put out some power, and I've never noticed any flex in the drive system. I literally can't tell the difference between the latest thing and my old UN71.

    Then again, they don't *make* the UN71 anymore... and I like the new stuff too.

    -Walt
    I'm just funnin' ya.

    Gotta go ride my ti softtail, with ti bars, stem and xt cranks now!

  14. #14
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    Quote Originally Posted by Walt
    I mean, I can put out some power, and I've never noticed any flex in the drive system. I literally can't tell the difference between the latest thing and my old UN71.

    Then again, they don't *make* the UN71 anymore... and I like the new stuff too.

    -Walt
    probably apples/oranges here and the bottom line is if it works for you than go with it, but...

    way back when I was doing a lot of trials competitions I had a number of stock bikes that all had the same issue...I could flex the ND crank arm into the ND chain stay during a big side-hop or rear wheel gap. I never analyzed it, but suspect it was a combination of crank flex and frame twist. For that reason, I feel that stiffer is better for me as whenever possible, I still incorporate as much trials type riding as I can on my MTB rides. I can't quantify anything, but I feel like the newer crop of external BB cranks are stiffer and it makes me warm and fuzzy. I won't project that on anyone else though.

    On the original topic...the integrated BB looks cool (to me) and in some cases can allow you to space your stays a tad wider. If you're building an SS bike with the intent to run the middle ring in the small position you can eek out a smidge more clearance without having to increase the bend angle. That's about it. Oh, and did I say they look cool?

    On a personal note, my personal road and CX bikes for this year were going to get the integrated BB shell and I think I just decided against it. The extra work required to ream and face the shell properly just isn't worth it to me at this point in time. The BB30 system can get away with a post-fab boring operation but the Shimano system needs boring and facing and at this point in time, there isn't anything out there to easily face the ends. One of these days, I'll make a spacer to allow the use of a Park facing tool, but until then I'm not likely to do many of these BB shells.

    Another thing on internal bearings, and this is total hypothesization - bearing crush might be an issue. I've noticed that the King Inset isn't a constant diameter on the press-in surface. The part of the cup that first is pressed into the HT measures 44.03mm with my crappy caliper. It maintains that diameter for approx 2mm and then tapers down to 43.92mm where the bearing sits. My assumption is that this allows a press fit without compressing the bearing. This may also be why Shimano uses a plastic cup. It's possible that the plastic can compress slightly without putting a great deal of compression on the bearing itself.
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  15. #15
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    Quote Originally Posted by Walt
    I mean, I can put out some power, and I've never noticed any flex in the drive system. I literally can't tell the difference between the latest thing and my old UN71.

    Then again, they don't *make* the UN71 anymore... and I like the new stuff too.

    -Walt
    I'm with you. I still use square taper in most my bikes. I've gone through a lot of ISIS bbs, and multiple Outboards, but I've never crapped out a square taper cartridge BB.

  16. #16
    pvd
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    Quote Originally Posted by smudge
    Another thing on internal bearings, and this is total hypothesization - bearing crush might be an issue. I've noticed that the King Inset isn't a constant diameter on the press-in surface. The part of the cup that first is pressed into the HT measures 44.03mm with my crappy caliper. It maintains that diameter for approx 2mm and then tapers down to 43.92mm where the bearing sits. My assumption is that this allows a press fit without compressing the bearing. This may also be why Shimano uses a plastic cup. It's possible that the plastic can compress slightly without putting a great deal of compression on the bearing itself.

    This makes a lot of sense.

  17. #17
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    Quote Originally Posted by CurbDestroyer
    I'm with you. I still use square taper in most my bikes. I've gone through a lot of ISIS bbs, and multiple Outboards, but I've never crapped out a square taper cartridge BB.
    I agree, they last well. My beef with sq taper is spindle twist, and to a lesser degree, wear on the crank tapers.

    My favorite is a mix of the two, the Octalink stuff (not DA). Tubular spindle, good bb life.. seems just like the old sq taper cartridges with with a beefier spindle. Now on it's way to obsolescense.

    Just picked up my first outboard bearing bb (King) for my new build.. we shall see. Lots of goofy o rings and plastic washers.

    -Schmitty-

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