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  1. #1
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    enlighten me... outboard bearings?

    My Carbon Land Shark was just outfitted with one of those outboard bearing bottom brackets to interface with its new SRAM cranks...

    pros and cons of those bb's?

    My buddy insisted to shed weight - it worked.

    I am so used to square taper...
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  2. #2
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    i know that because they have a larger bearing surface area (larger race, larger bearings) they are stronger than internal BB's.

    That's about the extent of my knowledge.

  3. #3
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    Larger bearings last longer, stiffer BB from the large-diameter hollow spindle, farther outboard support, etc... Lighter because of that big hollow pipe for a spindle. Been running them for a number of years with no problems.
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  4. #4
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    Also way easier to install and remove IMO.

  5. #5
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    Quote Originally Posted by ATBScott
    Larger bearings last longer, ...
    That might be true in theory but in real life they usually go bad way too early. At least on my bikes. Since they are outside they are exposed to the elements and sweat dripping from my face when climbing.

  6. #6
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    Quote Originally Posted by Minimalist
    That might be true in theory but in real life they usually go bad way too early. At least on my bikes. Since they are outside they are exposed to the elements and sweat dripping from my face when climbing.
    One issue - these bottom brackets require the BB shell to be faced. If the BB faces are not perfectly parallel, you will experience diminished service life.

  7. #7
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    Sweet frame. Assuming it's custom, why not a longer HT instead of so many spacers? What SRAM crankset is that?

  8. #8
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    Quote Originally Posted by ryker
    One issue - these bottom brackets require the BB shell to be faced. If the BB faces are not perfectly parallel, you will experience diminished service life.
    I am not sure about that. At least two frames I had the outboard bearings installed on were faced and the bearings still seized. IMO it is just a bad design.

  9. #9
    CB2
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    From my experience they weigh more.
    Race face turbines set up single (425g) + Raceface Ti square taper bb (175g) = 600g
    XT Hollowtech II set up single + outboard bearings= 750g.
    In the past I've had issues with bearing wear (and outboard bearings), but I've got my fingers crossed that won't be the case with my Swift, as it has a Phil Wood EBB.
    I believe the idea with outboard bearings was to give you the stiffness of the larger spindle octolink / isis bb, with the bearing life of square taper. I think they succeeded on the former, and were less successful on the latter.

  10. #10
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    Quote Originally Posted by Minimalist
    I am not sure about that. At least two frames I had the outboard bearings installed on were faced and the bearings still seized. IMO it is just a bad design.
    +1. Tho I see it as less of a bad design and more of a hack for the constraints of a small BB shell.

    I got more life out of square taper & ISIS than outboard. (Tho I can easily repack Truvativ outboard BBs to extend the life)

    Outboards are stiffer, perhaps the bolt-on interface is more reliable, maybe lighter. Pros and cons to everything.

    P

  11. #11
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    I liked the external Shimano BB setup on my Shimano Saints. When Chris King released their outboard bearings, it added to Hope and Phil Wood external BB offerings, it was yet another reason to jump to externals. I upgraded from the stock Shimano to Chris King without a notice of difference. The main thing were the crank arms, stiff, strong. The combo gave new life to an older frame accustomed to ISIS. But ironically I have sold off my externals and external cranksets and stuck with square taper (Phil Wood & Co.) using Middleburn RS7's with UNO no less. I just switched the square taper crankset to another bike after a full season of riding in the rain, wiped away the grime/dust from the Phil seals and rides like new in the replacement frame. From the numbers, the CK BB should save about 100-150g over a Phil Wood square taper BB with cups offering (not including the titanium or magnium varieties).
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  12. #12
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    Quote Originally Posted by deltasierra
    Sweet frame. Assuming it's custom, why not a longer HT instead of so many spacers? What SRAM crankset is that?
    I have no clue which SRAM cranks they are. Just got back from a 50 mile trip and they didn'tdissapoint.

  13. #13
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    Quote Originally Posted by deltasierra
    Sweet frame. Assuming it's custom, why not a longer HT instead of so many spacers?
    I think it is his love of the horizontal top tube.

    I like outboard cranks. SRAM bottom brackets tend to not last very long and I'm not impressed with their setup. I like Shimano's style better.

  14. #14
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    Quote Originally Posted by Schmucker
    I think it is his love of the horizontal top tube.

    I like outboard cranks. SRAM bottom brackets tend to not last very long and I'm not impressed with their setup. I like Shimano's style better.
    I am an inexperienced outboard user... when they start to fail, I shall renew.

    I am a little beetch for horizontal top tubes. I did move the stem lower before my ride today. About half way where it was when I posted the pics this morning.

    Now I am going to have a beer, and hide in the bath tub until Sarah gets back from her run...

  15. #15
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    Outboards work great unless they get wet. Then they seize really fast. Facing helps a little. DO NOT go to ceramics and get them wet. The races get worn quickly, then add water and they rust quickly. I know folks that are getting a yr or two out of theirs. Then I know folks that only got 50 miles on theirs(ceramic). I haven't seen a set of ceramics last more than ~3-500 miles. Not trying to argue here. If they work for you so far, more power to you.

    I run outboard ceramics on my roadie. It doesn't have very many miles on it, so there's no real info there.

  16. #16
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    betrayer of Square taper BB !!!! No I would assume the bearing would last longer seeing that water cant get through to them from the frame
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  17. #17
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    Quote Originally Posted by CB2
    From my experience they weigh more.
    Race face turbines set up single (425g) + Raceface Ti square taper bb (175g) = 600g
    XT Hollowtech II set up single + outboard bearings= 750g.
    In the past I've had issues with bearing wear (and outboard bearings), but I've got my fingers crossed that won't be the case with my Swift, as it has a Phil Wood EBB.
    I believe the idea with outboard bearings was to give you the stiffness of the larger spindle octolink / isis bb, with the bearing life of square taper. I think they succeeded on the former, and were less successful on the latter.
    CB2, years of reading have convinced me that you are credible. But likewise I know we are of different stature. Sadly, at 6'3", 200#, I dare not risk employing a ti sq taper bb. Wish I could, though. Happy trails (& roads) to you.

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  18. #18
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    External BB are a good thing, but they usually come with crap stock bearings. Once you slap some Enduro bearings in there (the cheap Enduros are fine) they'll last forever. Facing the shell is important.

    The Shimano external cranksets (aside from the new XTR) have a superior LH crank arm attachment method, and it's now impossible to round out a crank arm. ST killed too many of my crank arms (yes, they were properly torqued).

  19. #19
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    CK makes sweet Outboard bearing BB's that last about 100,000 miles longer than a stock Sram or Shimano. You can also regrease and rebuild them. And you can get pretty colors

  20. #20
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    Quote Originally Posted by Sparticus
    CB2, years of reading have convinced me that you are credible. But likewise I know we are of different stature. Sadly, at 6'3", 200#, I dare not risk employing a ti sq taper bb. Wish I could, though. Happy trails (& roads) to you.

    --Sparty
    I have a set of xtr 960's that weigh 592 with the external bottom bracket cups. I can't remember if I had a ring on when I weighed them, but it doesn't seem likely.

  21. #21
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    Less prop wash
    Quote Originally Posted by mikesee
    Better suited to non-aggressive 125# gals named Russell.
    I ride so slow, your Garmin will shut off.

  22. #22
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    The cranks look good, Ernesto.

    I splurged and bought an outboard BB two years ago, it seized up fairly quickly, so I repacked them and dealt with the non drive crank arm getting lose every ~50 miles. Meh.

    Square taper works better for my budget in any case. I'll try them again when I am a billionaire.

  23. #23
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    They last longer. I've been running my Shimano HT2 cranks for 5 seasons, and they have been in 3 frames. They are great for SS use because you can dial your chainline perfect every time. When they finally go bad, Chris King makes a EX BB, so I can add some bomb proof bling to my 9er.

  24. #24
    CB2
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    Quote Originally Posted by Sparticus
    CB2, years of reading have convinced me that you are credible. But likewise I know we are of different stature. Sadly, at 6'3", 200#, I dare not risk employing a ti sq taper bb. Wish I could, though. Happy trails (& roads) to you.

    --Sparty
    Even at 5'7" 140 lbs I have had my issues with cranks and BB's. I have broken 4 cranksets and a bottom bracket in the past 3 years. So I'll take the weight and possible limited life of outboard bearings for the confidence Shimano cranks offer.

  25. #25
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    Quote Originally Posted by CB2
    Even at 5'7" 140 lbs I have had my issues with cranks and BB's. I have broken 4 cranksets and a bottom bracket in the past 3 years. So I'll take the weight and possible limited life of outboard bearings for the confidence Shimano cranks offer.
    "Light, strong, cheap -- pick 2."

    We've all heard it before (thank you, Mr. Grumpy) and it's true. I built a 27.5# bulletproof FS sled once, complete with XL frame, 28" wide bars, 195mm cranks, fat tires and the whole shebang... very expensive. And bulletproof, like I said. Many would not consider 27.5# light, but I did (still do) for my size and durability demands.

    My current FS sled is a Salsa Big Mama @ 31# including 2.4" tires. Sure I'd love to drop 3-4# but I don't really care enough to make the investment. If I got your point above then I agree, sometimes a bit of extra weight, ie security via strength / durability, is worth carrying around.

    Take care.

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  26. #26
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    Just like other components, the lifespan of an outboard BB is going to depend on use, care, and manufacturer. I wrecked two FSA BBs on my cx bike in one season before investing in the Enduro press & replacement bearings (those did fine the remainder of the season & are still on the bike). I've had a SRAM Black Box ceramic-bearing BB that I got with a road bike in 2008 that now resides on my MTB. I take good care of it by cleaning and re-packing the bearings whenever I've been in a lot of mud or water, and it's still in great condition.
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  27. #27
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    Quote Originally Posted by Andrea138
    Just like other components, the lifespan of an outboard BB is going to depend on use, care, and manufacturer... I take good care of it by cleaning and re-packing the bearings whenever I've been in a lot of mud or water, and it's still in great condition.
    +1
    All of the outboard bearing BBs would have long life if we did that.

    Why the Shimano & Race Face BBs are unserviceable is beyond me. And why do we accept that?

    It certainly leaves room for Enduro & Chris King to fill the need.

    Just loaded up my Truvativ BB with Phil Wood grease last night. I have yet to toss out a BB since I started repacking. 2 years and going strong.

    P

  28. #28
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    My FSA ones that failed never gave me a chance- it just took one muddy CX weekend (Saturday and Sunday races in epic mud) for them to seize up completely. The Black Box bearings have gone through Hell and never let me down. The worst was Dirt, Sweat, and Gears last year. I posted some photos on my blog of the aftermath: http://blog.brickhouseracing.com/?p=1087
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  29. #29
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    I had bad experiences with early Race Face outboards. Chucked 'em and went to cheap Shimano square tapers. Thus far (years, no maintenance, hard riding in all weather) they've been flawless. I'm not especially big or aggressive, but did ride Arizona and Moab with no hesitancy when I lived down south.

  30. #30
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    Quote Originally Posted by Andrea138
    Just like other components, the lifespan of an outboard BB is going to depend on use, care, and manufacturer. I wrecked two FSA BBs on my cx bike in one season before investing in the Enduro press & replacement bearings (those did fine the remainder of the season & are still on the bike). I've had a SRAM Black Box ceramic-bearing BB that I got with a road bike in 2008 that now resides on my MTB. I take good care of it by cleaning and re-packing the bearings whenever I've been in a lot of mud or water, and it's still in great condition.
    I am a profound sweater and not very fast. That means, sweat is constantly tripping on the BB. To service my outboard bearings I would have to repack them every other week or so. I don't see the point of buying a crankset that I need to upgrade of the box.

  31. #31
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    I've had great luck with shimano outboard bb cranksets. I've been running a set of xts for 2 or 3 years now without replacement. They're also very easy to pull down for service, pinch bolts and splines are the only way to fly.

  32. #32
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    so I rode in the rain yesterday... should I now disassemble the gizmo, repack it, and go at it again?

  33. #33
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    I commuted on my RaceFace outboard BB through a Canadian winter and it still spins smooth. Maybe I'm just lucky.

  34. #34
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    Quote Originally Posted by Minimalist
    I am a profound sweater and not very fast. That means, sweat is constantly tripping on the BB. To service my outboard bearings I would have to repack them every other week or so. I don't see the point of buying a crankset that I need to upgrade of the box.
    I am the same way. My sweat eats through parts, too. I generally end up servicing them every month or so during race season (on both my road and MTB). As long as it's not a complete tear down/clean/re-pack (which I've only had to do twice because of crazy mud), it only takes about 10 minutes.
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  35. #35
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    Outboard bottom brackets suffer from a lack of support when compared to internal BB. The bearing of an internal BB are supported by being encased in the BB shell. External BB are supported by the threading, and the cantilever effect of the crank arms and axle on the bearing housings, can cause premature bearing failure. That fact that the bearing are set farther apart actually exacerbates this problem. Further, the cartridge bearing uses a carrier that reduces the bearing count (Yep, bigger bearings but only half the amount; gotta save weight you know). The combination of these two issues has eliminated the exterior bearings from most track use (Campagnolo and Miche still use an ISO square taper and Shimano uses an Octalink). RaceFace makes a "full-ball" (no carrier) downhill BB that holds up quite a bit better than most.
    Just one more rep and I get the toaster!

  36. #36
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    Quote Originally Posted by aka brad
    Outboard bottom brackets suffer from a lack of support when compared to internal BB. The bearing of an internal BB are supported by being encased in the BB shell. External BB are supported by the threading, and the cantilever effect of the crank arms and axle on the bearing housings, can cause premature bearing failure. That fact that the bearing are set farther apart actually exacerbates this problem. Further, the cartridge bearing uses a carrier that reduces the bearing count (Yep, bigger bearings but only half the amount; gotta save weight you know). The combination of these two issues has eliminated the exterior bearings from most track use (Campagnolo and Miche still use an ISO square taper and Shimano uses an Octalink). RaceFace makes a "full-ball" (no carrier) downhill BB that holds up quite a bit better than most.
    Any deflection in the external cups is going to be minute, I mean, really, really tiny. The cups are large diameter, and don't extend very far from the shell. One of the advantages of the cartridge ball bearings used is they're very tolerant of slight misalignment of the shaft. You're not getting any appreciable wear from the cups deflecting.

    The external bottom brackets also use bigger cartridge bearings, with bigger balls inside, and, in general, are rated for higher load. It's best not to try and second guess the engineers who designed the bearing, and rather simply look at what they're rated to.

    I don't think it's these reasons which have kept the external BB off the track, but rather a combination of marketing and an external's high q-factor.

    I really don't think it's necessary to go so far afield looking for a reason why external bearings fail, when the solution is as simple as "low quality bearings". As several people have already said, if you prep the frame right and put high quality bearings in there, they'll last quite nicely.

  37. #37
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    If durability is your main goal, you can't beat internal over outboard. Start Googling reviews of all the players (King, Hope, Shimano, Phil, etc.) and read reviews of the BB. The external bearing group you will read things like, "Got a a year . . . lasted three months . . . "X" brand last two years when my last "Y" brand last one" --- and then you get to the internal (Shimano UN54's, Phil, etc) and you read, "Haven't touched my in seven years and had it in five bikes." Rarely do you read of someone having one last less.

    At least that is what my research showed this past week as I was trying to decide on a White Industries crank w/Phil BB or an XT crank set-up with one of the aforementioned three. I went WI.
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  38. #38
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    Quote Originally Posted by bad mechanic
    Any deflection in the external cups is going to be minute, I mean, really, really tiny. The cups are large diameter, and don't extend very far from the shell. One of the advantages of the cartridge ball bearings used is they're very tolerant of slight misalignment of the shaft. You're not getting any appreciable wear from the cups deflecting.

    The external bottom brackets also use bigger cartridge bearings, with bigger balls inside, and, in general, are rated for higher load. It's best not to try and second guess the engineers who designed the bearing, and rather simply look at what they're rated to.

    I don't think it's these reasons which have kept the external BB off the track, but rather a combination of marketing and an external's high q-factor.

    I really don't think it's necessary to go so far afield looking for a reason why external bearings fail, when the solution is as simple as "low quality bearings". As several people have already said, if you prep the frame right and put high quality bearings in there, they'll last quite nicely.
    You know, I don't mind being disagreed with or even being wrong, but how about giving a little thought to some of your answers.

    It's best not to try and second guess the engineers who designed the bearing What? Do you really think engineers don't compromise strength for weigh?. Further by your own posting, the engineers spec'd low quality bearings that need to be upgraded.

    I don't think it's these reasons which have kept the external BB off the track, but rather a combination of marketing and an external's high q-factor Maybe you should actually "ask" someone at the velodrome before you explain their component decisions. The real answer is two fold; 1) drag from the seals, 2) noticeable deflection and drag as the inner race of the cartridge bearings bounce over the bearing carriers; something you probably wouldn't notice unless you are trying to maintain 50mph on a fixed gear.

    In my opinion the attempts to improve the square taper bottom bracket and still use a european shell was forced obsolescence; heck King designed the ISIS interface and then couldn't engineer a ISIS bottom bracket. Square Taper is simply the best compromise of bearing size and spindle diameter and still be encased inside the shell. The next real improvement is BB-30 (or BB83/BB86/BB90/BB92/BB94/BB95 “standards” now in circulation by bicycle manufacturers who don’t necessarily want to adopt the system of their competitors; Velo News); stronger, stiffer and lighter; a significant improvement over square taper
    Last edited by aka brad; 04-09-2010 at 06:12 PM.
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  39. #39
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    Quote Originally Posted by aka brad
    Oh No, engineers never compromise strength for weight.
    I'm talking about the engineers who made the bearing. If one bearing is rate for 250lbs and another one is rated for 500lbs (yes, those are hypothetical numbers), then I don't see any reason to start trying to agree it doesn't actually support a load as well. I'm comfortable taking a bearing's specs at face value.

    Quote Originally Posted by aka brad
    Maybe you should actually "ask" someone at the velodrome before you explain their component decisions. The real answer is two fold; 1) drag from the seals, 2) noticeable deflection and drag as the inner race of the cartridge bearings bounce over the bearing carriers.
    Track racers aren't the be all and end all of bicycle engineering and above marketing and sheep mentality. Also, there is no way the inner race of the cartridge bearing ever touches the carrier, much less bounces over it, that is, unless the bearing has grenaded.

    Quote Originally Posted by aka brad
    You really think it doesn't have anything to do with non-supporting gaps between the bearings?
    No, I don't think it does. I think it has to do with cheap bearings put in a more exposed location on the frame. Frankly, I find it interesting people try and find a more complicated explanation than that.

    Quote Originally Posted by aka brad
    In my opinion the attempts to improve the square taper bottom bracket and still use a european shell was forced obsolescence; heck King designed the ISIS interface and then couldn't engineer a ISIS bottom bracket. Square Taper is simply the best compromise of bearing size and spindle diameter and still be encased inside the shell.
    I feel the compromises made for housing the bearings inside the BB shell forces compromises elsewhere, and I feel those compromises are much more detrimental to the performance and longevity of the crankset/BB. I would much, much rather replace the bearings more often to gain the strength, sitffness, and to not round out another crankarm again.

    I'm not saying don't run ST if you don't want to, but the presenting ST as the high water mark of BB design is a bit much and ignores the compromises it has to make.

  40. #40
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    Quote Originally Posted by bad mechanic
    I would much, much rather replace the bearings more often to gain the strength, sitffness, and to not round out another crankarm again.
    I would rather do neither. I also have a hard time finding the faith in your technical expertise, but that might be your user name.

  41. #41
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    Quote Originally Posted by Minimalist
    I also have a hard time finding the faith in your technical expertise, but that might be your user name.
    Yeah, I get that.

  42. #42
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    Quote Originally Posted by aka brad

    In my opinion the attempts to improve the square taper bottom bracket and still use a european shell was forced obsolescence; heck King designed the ISIS interface and then couldn't engineer a ISIS bottom bracket. Square Taper is simply the best compromise of bearing size and spindle diameter and still be encased inside the shell. The next real improvement is BB-30 (or BB83/BB86/BB90/BB92/BB94/BB95 “standards” now in circulation by bicycle manufacturers who don’t necessarily want to adopt the system of their competitors; Velo News); stronger, stiffer and lighter; a significant improvement over square taper
    BB30 and similar will offer the best of both worlds. Long lasting 1/4" bearings, user friendly interface, and stiff, light, strong spindle.

  43. #43
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    The majority of my bikes have internal bearing bottom brackets. The external bearings that came stock on my bikes are garbage and last a few wet rides as opposed to years from the old school internal design. I've had Chris King headsets that have lasted years of hard winters, I'll look into his stuff next time.

  44. #44
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    Quote Originally Posted by bad mechanic


    Track racers aren't the be all and end all of bicycle engineering and above marketing and sheep mentality. Also, there is no way the inner race of the cartridge bearing ever touches the carrier, much less bounces over it, that is, unless the bearing has grenaded.


    No, I don't think it does. I think it has to do with cheap bearings put in a more exposed location on the frame. Frankly, I find it interesting people try and find a more complicated explanation than that.
    Starting with the second; I have no doubts cheap bearings and more exposure leads to a shortened life.

    The only case I make for track racers is they are hard on their equipment. I also did not say the inner race "touches the carrier", what I said is a carrier creates stationary gaps between the ball bearings leaving the race unsupported in these areas; this is done to save weight but also can cause pre-mature bearing wear. If this was not an issue with bearing wear, there would not be a heavy duty version without the carriers.

    Still, we agree there are some issues, that better bearings and maintenance (if the design allows) will help prevent pre-mature wear.
    Just one more rep and I get the toaster!

  45. #45
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    who the hell cares about velodrome riders?

    I think it is funny that we are big kids on big kids bmx bikes.

    Bmx used the larger (american, cruiser style) BB forever. why?
    because bigger bearing are stronger. end of debate.
    but bmx knew to put the bearings in the frame.
    well time has gone on and now bmx offers many different kinds of BBs.
    standard, euro (ST to us), spanish, and mid.
    the last two (the newest players) being press fit sealed bearings, omg! BB30!!!
    so 10 years later mtb is ready to follow suit.

    in the mean while you clowns will just argue over the lesser of two evils.
    but, hey, its the internet and I'm bored. thanks for the entertainment.
    no chain no gain.

  46. #46
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    im still using old race face cranks with a ti square taper bb. just buy myself new 20$ bearings every couple seasons and im good to go.

  47. #47
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    Quote Originally Posted by LFASS
    im still using old race face cranks with a ti square taper bb. just buy myself new 20$ bearings every couple seasons and im good to go.

    Spend a bit more and get SKF or INA. I replaced my original Enduros with SKF seven years ago. They still spin fine.
    aLaN AT BikeMojo DOT com

  48. #48
    Mtbr Forum Sponsor - Homebrewed Components
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    i am using the original bottom bracket for my Shimano xtr m960 cranks, and these are probably 7+ years old? Still spin as good as new. I think there is more of a chance for incorrect installation so bearing life could suffer, but besides that, i wont go back to internal bearing stuff.

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