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  1. #1
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    Bottom-brackets, old ways better?

    So I'm rebuilding a friend's bike -- an old, Bianchi Avenue hybrid.

    Last night I cleaned and regreased his bottom-bracket bearings. First time I've ever worked on a cup-and-cone bottom-bracket.

    A good spin of his cranks now easily nets me a over a dozen revolutions of the pedals. I just got 14 revolutions without trying hard.

    By contrast, none of my newer and "better" bikes even comes close. I have three bikes with Shimano XT external-bearing bottom-brackets, and I'm not sure I even get three revolutions of the pedals when I spin their cranks. I certainly get nowhere near a dozen.

    I'm sitting here now, wondering how much of my energy is lost in spinning my XT cranks and whether it might be a good idea to go and invest in some square-taper cranks and bottom-brackets. (Not sure I can find cup-and-cone for mountain-bikes).

    I'm looking at this 10-year-old bike, and I'm thinking that perhaps the industry has gone backwards rather than forwards here.

  2. #2
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    At the risk of sounding like a retro grouch, you've "discovered" what most of us over 35 have known for years. Much of the progress in BB's has been backwards.

    Time was when the original BB would still be in service when the frame went to the scrap heap. In many cases that was without any service.

    Part of the impetus for the move to cartridges came from the bike builders who wanted to get away from the time and skill involved in assembling BB's into the frame. Hence the cartridge, shipped pre-adjusted (non-adjustable) and ready to just drop in by any monkey on the assembly line.

    I should note that the bike industry is only following trends throughout the world. Serviceable assemblies are being replaced with modular construction wherein a problem component isn't repaired or adjusted, but simply replaced. Look at anything, cars, computers, appliances, etc. Skilled mechanics and things that need them are going the way of the dodo bird, and being replaced with modules and module replacers.

    We call this progress.
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  3. #3
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    Finding decent cranks and bb's for square taper isn't easy. And will only get harder. It'll be around for years, but slipping towards Huffy level quality.

    I still have not changed (most of) my bikes past square tapers.

    Square tapers had their drawbacks too, but they also had an extended time in development too. ISIS, Octalink, and now outboard cranks don't have the same time frame in development. I still think those 'standards' could have provided similar levels of quality given even decent development time. But the 'standard' changes quickly enough to make my cranks 'retro'.

    And lets not forget that some of the square taper cranks and BB's were pretty bad too. There were reports of bent spindles, bearings fried, cranks that wallowed out, random creaks, etc. I wonder why when we get nostalgic, we forget the things that were a pain about the old stuff. I've seen people who still love threaded headsets too...

    Square taper has three big benefits - they spin smooth (and like you noticed free bearings spin smoother than even cartridge bearings (in general) ), that you can meddle with chainline much, much easier, and you can (or least could) piece together a pretty lightweight setup for not too much coin.

    The biggest things I'm seeing is most of the cranks are becoming industry friendly. Two sizes for the crankarms, and that's it. Much less to worry about from the manuf's point of view - we don't have to worry if our tolerances match those of another company's BB - because it's OUR BB! We don't have to worry about making different, and hard to sell, sizes of BB, since it's one size fit all. Our costs can be streamlined, because we don't have to worry about selling the BB and crank as two pieces, or six different bb sizes, or four sizes of cranks (those were the days, 170, 172, 175, etc...).

    And since we sell the cranks as a unit - we can control final retail price better. No more worries that the XT BB and the LX Crank turn out to be a better value and seller than the 'complete' XT setup. Or that our $40 crank and a $50 BB is almost as light as our top end. (See Deore Hollowtech arms, aftermarket rings, and a decent BB)

    I'm a cynic and a retro-grouch, but I want improvements to make the bike work better, not to improve the bottom line. ISIS didn't do that, Octalink didn't do that (I think they had 4 different spindles going at one point), and outboard cranks are debatable at this point, with me not holding out much hope.

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  4. #4
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    Quote Originally Posted by JmZ
    Finding decent cranks and bb's for square taper isn't easy. And will only get harder. It'll be around for years, but slipping towards Huffy level quality.
    I did do some looking around yesterday, not so much for square-taper per se, but for anything using internal rather than externalized bearings. Race Face's site didn't list anything. Shimano uses external bearings for all but their really low-end cranks.

    I did find Middleburn cranks on the Chain Reaction Cycles site. Those look interesting, and can be had in both square-taper and ISIS. Then it would be a matter of finding quality bottom-brackets of those types.

  5. #5
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    Sealed unit square taper bottom brackets are still available. I just ordered a UN-54 for my old Bianchi. The cup and cone BB just didn't want to stay adjusted anymore. I'm not sure why, but after every ride the adjustment would back off. I tried locktite, different adjustment methods, but it still came loose. It wasn't worth the headache anymore, with a sealed square taper unit available for $24 at Speedgoat. IIRC Jenson has them too, so does Tree Fort.
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  6. #6
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    I wonder if you did the crank-spin test on external ceramic BBs if they'd outspin a cheap old shimano cartridge BB (like an LP20) or an Octalink/ISIS BB setup (for an equal weight of crankarm and pedals... more weight on the outside of the arm means more momentum to keep the sucker spinning afterall). I'm betting simply having the fanciest bearings around still won't make up for the drag of the seals on the external BB units.

    As to shimano's current octalink offerings. They make them up to the Deore level still, and they're still fairly stiff and light if you get one of the hollowtech arm models. The engineering rule of thumb was always "strong, light, cheap... pick 2" until shimano came along and trickled the higher end technology and tooling down to the lower price level parts once they'd been paid off in previous years making the fancier parts. Of course that just solves the crank arm part of the equation. As pointed out above, you still need to source chainrings and a bottom bracket. Neco makes some nice sealed cartridge bearing BBs with alloy cups around the old UN-7x weight for square tape.
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  7. #7
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    Quote Originally Posted by JonathanGennick
    I did do some looking around yesterday, not so much for square-taper per se, but for anything using internal rather than externalized bearings. Race Face's site didn't list anything. Shimano uses external bearings for all but their really low-end cranks.

    I did find Middleburn cranks on the Chain Reaction Cycles site. Those look interesting, and can be had in both square-taper and ISIS. Then it would be a matter of finding quality bottom-brackets of those types.
    Two words: Phil and Wood (for square-taper cranks, anyway).
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  8. #8
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    Lets not get too misty eye'd about square taper. It just wasn't intended to stand up to MTB use. Plenty of broken/bent spindles, wallowed out crank arms, and FLEX in 20+ years of use on mountain bikes.

    Both isis and external bearings can work very well, but have their own quirks....
    Last edited by turbodog; 04-01-2009 at 10:19 AM.

  9. #9
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    Quote Originally Posted by JonathanGennick
    So I'm rebuilding a friend's bike -- an old, Bianchi Avenue hybrid.

    Last night I cleaned and regreased his bottom-bracket bearings. First time I've ever worked on a cup-and-cone bottom-bracket.

    A good spin of his cranks now easily nets me a over a dozen revolutions of the pedals. I just got 14 revolutions without trying hard.

    By contrast, none of my newer and "better" bikes even comes close. I have three bikes with Shimano XT external-bearing bottom-brackets, and I'm not sure I even get three revolutions of the pedals when I spin their cranks. I certainly get nowhere near a dozen.

    I'm sitting here now, wondering how much of my energy is lost in spinning my XT cranks and whether it might be a good idea to go and invest in some square-taper cranks and bottom-brackets. (Not sure I can find cup-and-cone for mountain-bikes).

    I'm looking at this 10-year-old bike, and I'm thinking that perhaps the industry has gone backwards rather than forwards here.
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  10. #10
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    Quote Originally Posted by turbodog
    Lets not get too misty eye'd about square taper.
    It's probably not the square taper per se, but rather the issue of internal versus external bearings. All of my bikes with internal, bottom-bracket bearings -- whether square taper or ISIS -- have cranks that spin far more easily than my bikes with externalized bearings. The Bianchi that I just rebuilt is a particularly startling example of that. So I have to ask the question: Why can't my expensive, XT cranks spin like those on my friend's 10-year-old, cheap, Bianch Avenue? Is it really helping me to have to pedal harder? Aren't bearings supposed to make things easier, not harder?

  11. #11
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    Having repacked way too many loose-ball BB's, I have little fondness for them. IMHO, the contact seals are the source of the drag, more so than the bearings. I had a nice Chorus-equipped road bike back in the day. You could spin the crank and it would just go and go and go. Sadly, anytime I rode in the rain, I would have to repack the bastard because the super-smooth, low-fiction seals let in all kinds of crap without so much as a hey-how-ya-doin'. Eventually, I realized that the seals were only there to keep the grease from getting out. Over the years I've used WTB GG, a variety of UN**, FSA, Syncros, Truvativ, generic and SRAM BBs with varying results.

    FFWD to today. The outboard bearings in my XT cranks spin about as well as the day I got them in 2004. They are on their second frame. The bearing assemblies have been out of the bike twice, once when switching frames, and once to see if they needed any servicing. They didn't. No, they don't spin as smooth as the Chorus BB did, but at least I don't have to tear them down after every other ride. It's totally worth the ~0.1% efficiency loss in the drivetrain to not have to mess with them umpteen times a year.

  12. #12
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    I had nothing against square tapers, either loose ball type or cartridge. Never had a problem with them except availability (this goes to 5 arm vs 4arm, and different bcds as well as bb type) as the industry moved on. I do like that I can remove my Shimano external bb type crank arms more easily and with fairly standard tools (well, except for that FC16 thing, but still easier than a puller), and bearing servicing is now something I can do unlike the cartridges (well, most of them). Can't wait for the next "standard", though...
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  13. #13
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    Quote Originally Posted by JonathanGennick
    So I'm rebuilding a friend's bike -- an old, Bianchi Avenue hybrid.

    Last night I cleaned and regreased his bottom-bracket bearings. First time I've ever worked on a cup-and-cone bottom-bracket.

    A good spin of his cranks now easily nets me a over a dozen revolutions of the pedals. I just got 14 revolutions without trying hard.

    By contrast, none of my newer and "better" bikes even comes close. I have three bikes with Shimano XT external-bearing bottom-brackets, and I'm not sure I even get three revolutions of the pedals when I spin their cranks. I certainly get nowhere near a dozen.

    I'm sitting here now, wondering how much of my energy is lost in spinning my XT cranks
    Very, very, little.

    That's the seals that are dragging. You also will notice that newly packed bearings often don't spin as freely as ones that are low on grease.

    There may be other reasons to go back to square taper, but I don't think this is one of them.
    Last edited by kapusta; 04-02-2009 at 08:24 AM.

  14. #14
    JmZ
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    Yup

    Quote Originally Posted by JonathanGennick
    I did do some looking around yesterday, not so much for square-taper per se, but for anything using internal rather than externalized bearings. Race Face's site didn't list anything. Shimano uses external bearings for all but their really low-end cranks.

    I did find Middleburn cranks on the Chain Reaction Cycles site. Those look interesting, and can be had in both square-taper and ISIS. Then it would be a matter of finding quality bottom-brackets of those types.
    It's about $$$. Phil Wood, White Ind, SKF are at the top of the chain. Then you've got some Euro brands that I'm less familiar with, then you get Interloc, SINZ, and others, and UN-5X series.

    It gets even more difficult if you need a 73mm shell.

    Middleburn is one of the last high end cranks available. I almost want to say 'the last', but then someone will show me another.

    My suggestions are to watch E-Bay. Normally RF Turbines, UN-7X, and Race Face BB's come up on a fairly regular basis (sometimes even NOS), but how long will that source last?

    Good luck,

    JmZ
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    a few comments of my own:

    1. i dont think the drag has any real effect. it steals power, sure, but not enough to notice.

    2. the outboard bearings allow for larger bearing balls. everybody says its good, right?

    3. the integrated crank design is noticeably more rigid. i dont know whether its the larger spindle diameter, or the fact that its connected to the drive side arm, but it is. i only weigh 155 lbs, and i was really impressed with the difference.

  16. #16
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    Last year i bought a 1992 XTR M900 crankset with a 1992 UN-91 square taper BB on ebay, it got used everyday for 7 months and there is a lot of mud sand all the time here, i even rode for at least 25 minutes with water up to the handlebars (I know this is not a good idea) so it was completely submerged. I haven't toutched it since the instalation. I just did the revolution test and got 18 full revolutions!!

  17. #17
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    I had the same "disturbing" realization....until a few days after installation when I realized that the drag was nearly gone. I chalked it up to the seals conforming to the rest of the parts and the grease in the bearing housing spreading around and distributing in an efficient manner. True....the first spin test was disturbing....but after a few hours in the saddle....the 2nd spin test was nearly identical to the older BB....only it was smoother. Soooooooo......whats my point? The difference after breaking in was negligible....I'm not saying you don't have a point....but I am saying that a break in period is necessary to reach optimal conditions after a rebuild or new installation.

  18. #18
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    i just upgraded this year to the hollowtech/external bottom bracket replacing a set of 93' deore lx (5 arm, 110/74) cranks and a cartridge bottom bracket. frankly, i won't ever go back. the bottom bracket is so much stiffer (flexing wise). i bent 3 bottom brackets previously on my bike and after the last one i just said screw it and rode it bent for 10 years. yeah, it spun better than the current setup, and my old road bike was even more old school with the cup and cone, but it was flexy. you might think we've gone backwards in bb design, but i think the companies have been looking to get the flex out of the design and they have certainly done that. i like the hollowtech/externall bb setup so much i am looking to get it for the road bike (and also going to a compact crank - but thats another story for another forum).

  19. #19
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    For MTB, I'd take the HTII set-up over square taper every time. If the drag bothers you, get Hope bearings - you'll wonder how you ever lived with the drag on your square taper BB.
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  20. #20
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    Quote Originally Posted by JonathanGennick
    So I'm rebuilding a friend's bike -- an old, Bianchi Avenue hybrid.

    Last night I cleaned and regreased his bottom-bracket bearings. First time I've ever worked on a cup-and-cone bottom-bracket.

    A good spin of his cranks now easily nets me a over a dozen revolutions of the pedals. I just got 14 revolutions without trying hard.

    By contrast, none of my newer and "better" bikes even comes close. I have three bikes with Shimano XT external-bearing bottom-brackets, and I'm not sure I even get three revolutions of the pedals when I spin their cranks. I certainly get nowhere near a dozen.

    I'm sitting here now, wondering how much of my energy is lost in spinning my XT cranks and whether it might be a good idea to go and invest in some square-taper cranks and bottom-brackets. (Not sure I can find cup-and-cone for mountain-bikes).

    I'm looking at this 10-year-old bike, and I'm thinking that perhaps the industry has gone backwards rather than forwards here.
    I think people are taking this "spin test" way to seriously, and not even understanding what it tells you. Who says it is even a good thing for it to spin 15 times instead of 5 times? An old bb with shot seals that has lost nearly all it's grease will often spin very freely on the stand, more so than a new one. New seals often cause more friction than shot ones, and grease (which most would agree is a good thing) slows down the bearing as well.

    This is a seriously flawed test.

    Again, I don't have an external bb vs square taper opinion, but please see this "test" for what it is.

  21. #21
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    Quote Originally Posted by SteveUK
    For MTB, I'd take the HTII set-up over square taper every time. If the drag bothers you, get Hope bearings - you'll wonder how you ever lived with the drag on your square taper BB.
    a common misconception

    the hollowtech is the hollow arm. the outboard bearings is the integrated crank design.
    there is such a thing as an octalinck hollowtech:
    http://www.dirtragmag.com/print/arti...=stuff_reviews

    no reason why a square taper bb wouldnt have hollowtech crank arms

    ive also seen an integrated crank (outboard bearings) which didnt have hollowtech arms - the sales rap said it was an oem lx

  22. #22
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    Quote Originally Posted by brake jack
    no reason why a square taper bb wouldnt have hollowtech crank arms
    I understand that you are pointing out that hollowtech and square taper refer to different things, and theoretically you could have square taper hollowtech arms, but I don't think that Shimano in fact ever made them.

  23. #23
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    Quote Originally Posted by brake jack
    a common misconception

    the hollowtech is the hollow arm. the outboard bearings is the integrated crank design.
    there is such a thing as an octalinck hollowtech:
    http://www.dirtragmag.com/print/arti...=stuff_reviews

    no reason why a square taper bb wouldnt have hollowtech crank arms

    ive also seen an integrated crank (outboard bearings) which didnt have hollowtech arms - the sales rap said it was an oem lx
    i miswrote and should have said hollowtech II, which only comes as the integrated spindel. yes, the hollowtech did come as the octalink

  24. #24
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    Quote Originally Posted by brake jack
    a common misconception

    the hollowtech is the hollow arm. the outboard bearings is the integrated crank design.
    there is such a thing as an octalinck hollowtech:
    http://www.dirtragmag.com/print/arti...=stuff_reviews

    no reason why a square taper bb wouldnt have hollowtech crank arms

    ive also seen an integrated crank (outboard bearings) which didnt have hollowtech arms - the sales rap said it was an oem lx
    HollowTech = hollow out arms
    HollowTech-II = external BB with 24mm hollow BB shaft.

    FC-M532 - non-series Shimano HollowTech-II cranks that are not HollowTech (ie: no hollow arms).

  25. #25
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    "a common misconception..."

    You'll note if you read my post again that I refer to the HTII (two) set-up, which uses, exclusively, outboard bearings. I've used other (Truvativ) outboard set-ups, but was referring, in this case, specifically to Shimano's HTII set-up.
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