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  1. #1
    kellyme
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    What BB width with Paul Disc Word and XTR 952 crank.

    I plan to run a Shimano 105 BB, but can i use the 109,5 mm on my new Kelly SS?
    Last edited by larutaviking; 05-27-2004 at 09:05 AM.
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  2. #2
    kellyme
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    For this one

    One happy Norwegian.
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    Put me back on my bike!

  3. #3
    mtbr member
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    Unfortunately,...

    Quote Originally Posted by larutaviking
    I am planning to run a Shimano 105 BB, but can i use the 109,5 mm on my new Kelly SS?
    The 105 BB won't work with the XTR cranks, different spline pattern. As far as the size for your drivetrain I am unsure. I use the 109.5 with my M952 and Chris King SS hub.

    Good Luck with your build!

  4. #4
    kellyme
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    Quote Originally Posted by Diesel
    The 105 BB won't work with the XTR cranks, different spline pattern. As far as the size for your drivetrain I am unsure. I use the 109.5 with my M952 and Chris King SS hub.

    I'll go with an XTR 952 BB then in 109,5.
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  5. #5
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    Quote Originally Posted by Diesel
    The 105 BB won't work with the XTR cranks, different spline pattern. As far as the size for your drivetrain I am unsure. I use the 109.5 with my M952 and Chris King SS hub.

    Good Luck with your build!
    Akshully, Gordon (BTW - how's things?), the 105 bb will work with XTR cranks. It just won't work with XT/LX or Deore Octalink cranks. The XTR cranks share the same spline with 105, Ultegra and Dura Ace cranks (and bottom brackets). The depth of the splines for these cranks is 5mm. The depth for bottom brackets to fit XT/LX and Deore cranks is 9mm.

    So, yes, the 105 bb will work with the XTR cranks. But, the Paul WORD hub is for a threaded f/w (unlike the King cassette hub) so there is not much room for moving the rear gear to align for optimal chainline once you bolt on the cranks to that 109.5mm bb. The M952 cranks were made to work with the 112.5mm XTR bb for a 47.5mm chainline (mesured with the chainring in the middle position) - which is also what the Paul hub w/ freewheel is.

    It might be possible to run a narrower bb, but you will have to play around with spacers under the fixed cup flange or behind the freewheel to dial in your chainline. A handfull of 1mm spacers is vital to have for the dedicated ss'er. The diameter of the bb cups and the freewheel threads are the same so the spacers can be used at either spot. You might also have to run your chainring where the large chainring would typically go - that is if you are running the XTR spider too and not something like a Boone or Jericho splined chainring which can't be spaced in or out.

    But when all is said and done, I like narrower BB's with XTR to reduce the Q-Factor. When all the pro's were running 952 XTR, they all ran them as doubles with Dura Ace bottom brackets to maintain a low Q-Factor that matched their road bikes.

    All this is only related to crank/bb fit. As for fitting to the Kelly, there shouldn't be any reason why it wouldn't fit unless your Kelly has incredibly wide chainstays than won't allow the crank arms to be installed with a narrower bb - but it should.

  6. #6
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    Mistake??

    Quote Originally Posted by larutaviking
    I'll go with an XTR 952 BB then in 109,5.
    I think that the 952 BB is only available in 112.5 and 116, both fit 68 or 73mm shells. I believe that the same is true of the 950 BB which is rebuildable.

  7. #7
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    I correct myself I use the 112.5 M952 BB...but,

    "Akshully, Gordon (BTW - how's things?), the 105 bb will work with XTR cranks. It just won't work with XT/LX or Deore Octalink cranks. The XTR cranks share the same spline with 105, Ultegra and Dura Ace cranks (and bottom brackets). The depth of the splines for these cranks is 5mm. The depth for bottom brackets to fit XT/LX and Deore cranks is 9mm."


    Mike,

    You missed a great ride at SART last weekend. I am sure you were busy up at Nationals. I talked to Dan B while he was up there (he was hanging out with Wayne). I am heading up to Mammoth this weekend for some R/R and a whole bunch of riding.
    Last edited by Diesel; 05-27-2004 at 09:41 AM. Reason: Wrong spec...

  8. #8
    Team SUMMIT BICYCLES
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    I'm running Dura Ace

    I'm running a Dura Ace 7700 bottom brackett with my 950 cranks (I think they are identical to the 952's?) and an ENO hub. I don't have any problems with the 109.5 mm spindle and using the middle chainring position. I am waiting on a Boone ti chainring, so we will see if the chainline works out still.
    I wanted to make the Dura Ace bottom brackett work because it is so much lighter than the XTR (about 70 grams lighter at 173gms) and the better Q factor.
    If you have the chainstay clearance for the cranks and can make the chainline work (spacers on freewheel, bottom brackett or putting chainring in outer ring position), this system is much lighter and seems to do the job just as well.

  9. #9
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    Follow up to 952/105 bb fit

    I called my buddy at S h i m a n o who confirms that the road bottom brackets are compatible with XTR 952 cranks. But, I now have some reservations after performing an extensive scientific test at the possible expense of two left side 952 crank arms. Here's what I found.

    The splines (there are 8 of them on all S h i m a n o OCTAlink bottom brackets - 2.2mm wide on 952 and road, 2.5mm wide on XT/LX/Deore) - anyway back to the splines, the splines on the road bottom brackets have a small radius at the base of each spline. The 952 bottom bracket doesn't have nearly as much of a spline and to the nekkid eye looks square. It also appears that the XTR 952 crank to spline interface is machined to match the 952 bottom bracket. How do I know this? Well, when I installed my 952 crank on a road bb, the radius of the spine knocked some metal off the corner of the crank spline interface - effectively rounding out the corner.

    What does this mean? Ideally the 952 bottom bracket is best used with the 952 crank. If you insist to use road bottom brackets with 952 cranks, be prepared to accept the results shown in the crank photo. I explained all this to my buddy at S h i m a n o and he still thinks they are interchangeable. The amount of meterial removes is negligible. But, it you go with a road bb, I would continue to use road bb's with that crank. Personally, I will put my 952 arms back onto my 952 bb without any worry on my part.

    So there you have it.

    Gordon - never made it to Big Bear either. My plan was to race Big Bear on Saturday and head down to the SART ride Sunday. But since just having arrived back home from 10 days in Asia, my wife thought it best to spend some time with the family. I did a really fun ride at Penasquitos on Sunday, though with her and my kid.
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    Last edited by ssmike; 08-19-2006 at 09:04 AM.

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