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  1. #1
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    Integrated Bottom Bracket Crank Questions

    Ok, I've searched this forum with no luck so sorry if this has already been discussed to death but...
    Seems that all the high end cranksets are going to the integrated bottom bracket (also heard it referred to as "external bearing"). First XTR, now XT, FSA, and next year's Truvativ Stylo will only be offered this way.
    Questions: What are the advantages / disadvantages of the integrated setup? With the external bearings are the cranks farther away from the centerline of the bike? If I get a standard crankset and BB today will it be obsolete in a few years? I'm not a pedal masher by any stretch so BB strength is not really an issue. Any comments would be greatly appreciated.
    - Thanks.

  2. #2
    A Midwesterner in Europe
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    Well,

    A lot of companies are making and switching to this design mainly because there are several advantages that make this new design superior to old ISIS splined BB/Crank combos.

    The biggest is the BB bearings. If you were to pull apart your ISIS BB you would find lots of small ball bearings. Small bearings don't have very high tolerances and in some cases don't last very long. They had to make the bearings small in order to fit the large ISIS spindle inside the BB. So to have a big pipe-like axel the bearings have to be smaller to accomodate.

    You'd also notice that the BB bearings in an ISIS BB are not near the edge of the cartridge unit but in a little bit.

    With the new designs they can run larger ball bearings because the put them on the outside of the BB shell and they can also run a huge spindle. And now that the bearings are on the outside of the BB shell the new gigantic spindle they use has a wider platform to sit/spin on. The bearing placement difference from an ISIS to a X-Type/External/Hollowtech 2 is about 40mm or 4 cm wider.

    So now we have really stiff cranks, big bearings, lighter BB's, cheaper BB's, wider bearing placement.

    As far as compatiblity goes. All the BB's are cross compatible. So you can use a Race Face BB on a Shimano Crank if you want. There are some design differences between the Race Face Cranks and the Shimano but it's all the same idea.

    Shimano will have a LX crank coming out soon, it's gonna retail for about $90-100 plus about $30 for the BB.

    Ride a bike with one road or mountain, there is a difference and it's nice.

    I hope that all helped.

  3. #3
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    New question here. Bearing drag...

    JK -
    Thanks for the details. Very helpful. I went with the XT integrated setup and was surprised to find that they don't spin freely at all - ie: with just the cranks installed (no chain, no pedals) the cranks will not free spin even one full revolution. The drag is not binding or uneven, it's consistent and makes a slight "shhsh" sound. Is this normal? My FSA isis BB and cranks spin with no decernable drag whatsoever. The XT cranks were shop installed and the frame BB was chased but not faced (because it's a Blur and the lower pivot gets in the way). Thanks again for any thoughts.

  4. #4
    A Midwesterner in Europe
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    The drag is normal. You just need to ride. They over pack the bearings from the factory, it doesn't hinder the performance of the BB at all, you think it would but it's fine. The XT BB is regarded by many as the better one from Shimano.

    It would be really nice to have gotten the BB shell faced. I've not seen an up close picture of the pivot on the Blur, but I'm sure there is a way to get it done properly.

    Enjoy the ride!!

  5. #5
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    Making the jump

    Seems like the jump from ISIS to Outboard Bearing type BBs is worth it. I just started noticing degradation of my ISIS BB and it's not even that old, but not as if it was special our anything.

    I think I'm going to upgrade it soon after I get my next fork, here my choices, but I am living in Japan, mind you I'm in the US Navy.

    RaceFace Evolve DH - $170

    Shimano Saint - roughly $230
    Shimano Deore XT - Roughly $180

    What would be my best bet?

  6. #6
    A Midwesterner in Europe
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    It really depends on what type of riding you are doing.

    The XT is very nice. The Saint is overpriced I think. But then again RACE FACE makes a pretty nice one as well. I opted for a Race Face. You have a couple of options with it, like adjustable chainline via some spacers on the spindle.

    Shimano is also releasing a LX version and a Hone version which is similiar to the Saint, but cheaper. It's pretty much an LX crank that is black.

    Good Luck.

  7. #7
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    question on facing?

    Sorry for the stupid question, but what exactly does it mean when you say to have it faced? I have heard this before & just never thought to ask. Thanks in advance for nay info you can give me.

  8. #8
    A Midwesterner in Europe
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    It's not a dumb question at all.

    Basically you are making sure the surfaces of the BB shell are perfectly flat. Look at the pictures in the link and you'll get the idea. You can read the procedure as well, especially the top portion under "tools needed" to get a better understanding of it.

    http://www.parktool.com/repair_help/howfix_bbtap.shtml

    Hope that helps.

  9. #9
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    Quote Originally Posted by j.king
    It really depends on what type of riding you are doing.

    The XT is very nice. The Saint is overpriced I think. But then again RACE FACE makes a pretty nice one as well. I opted for a Race Face. You have a couple of options with it, like adjustable chainline via some spacers on the spindle.

    Shimano is also releasing a LX version and a Hone version which is similiar to the Saint, but cheaper. It's pretty much an LX crank that is black.

    Good Luck.
    So the XT might be the way to go, is there a good bashguard that I can put on it to replace the big ring, I'll be removing it because I almost never use it.

  10. #10
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    very much, thanks

    I'm still such a newbie & my bf isn't always around to help, so thanks for the link with all the info, I really appreciate it.

  11. #11
    A Midwesterner in Europe
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    TruVativ, Race Face, and Shimano all make pretty nice bashguards.

    TruVative has one that is really nice, but its a hard plastic.

    You'd be best off with a Race Face one, just make sure you get the proper Bolt Circle Diameter measurement. For it to fit right.

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