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  1. #1
    Senior Member mijome07's Avatar
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    which size BB spindle width for my 1x9 setup?

    I have a stock Truvativ Touro 50/36 compact crankset with a 68x108mm BB and a 45.5mm chainline (?). Pretty much an outdated square tapered crankset. And a 12-26T 9-speed cassette in back. I'm leaning towards a 34T x 11-32T setup.

    The BB needs to be replaced and my options seem limited. I found a Shimano UN54 BB in 2 potential sizes. Reviews seem pretty good and they are cheap.

    I'm trying to get the straightest chainline for this setup. Should I get a 68x107mm and run the chainring on the outside (I'm adding 2 bashguards) or get the 68x113mm and run the chainring on the inside?

    Is there something I'm missing? This is all new to me. I'll appreciate your comments and/or expertise.
    Last edited by mijome07; 06-16-09 at 04:20 PM.

  2. #2
    PhatFree
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    are you setting this up for the road or mtb? I have a Karate Monkey set up with a 32x11-32 so this is why I ask. 32 in the front is kinda low for road use. I run a 42x12-25 on a steel road bike.
    At any rate, on the KM I run a bash guard on the outermost ring spot, have the ring in the middle position and run a jumpstop to prevent the chian from falling in. I have not had any problems. Sorry, that I can't actually address your question about bb length. When I built up the KM I put the ring on the outside, then on the inside and sighted down the chianline. Picked the postion that seemed best and went riding.

    Good Luck!!

  3. #3
    Senior Member mijome07's Avatar
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    Sorry, I forgot to mention what kind of riding. This will be on my cyclocross bike. So road and off-road. I plan on touring and bikepacking with this bike. And I'll be hauling a light 'rackless' load.

  4. #4
    PhatFree
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    I was at the bike shop this weekend and I saw a Chili Con Crosso built up with a 42x11-25. I believe the bike was built specifically for cx racing. If you have both rings I would try them out and see which one you like. You can run endless gear calculations but will never know if the gearing is right until you get out and ride. You could also run a wide mtb cassette.

  5. #5
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    Quote Originally Posted by mijome07 View Post
    I have a stock Truvativ Touro 50/36 compact crankset with a 68x108mm BB and a 45.5mm chainline (?). Pretty much an outdated square tapered crankset. And a 12-26T 9-speed cassette in back. I'm leaning towards a 34T x 11-32T setup.

    The BB needs to be replaced and my options seem limited. I found a Shimano UN54 BB in 2 potential sizes. Reviews seem pretty good and they are cheap.

    I'm trying to get the straightest chainline for this setup. Should I get a 68x107mm and run the chainring on the outside (I'm adding 2 bashguards) or get the 68x113mm and run the chainring on the inside?

    Is there something I'm missing? This is all new to me. I'll appreciate your comments and/or expertise.

    You been drinking too much of the Outboard Bearing, Latest-is-the-greatest Kool-Aide I see

    No, square tapers are not out of date, nor inferior. There's many BB's to choose from, and Shimano is far from you only choice, I wouldn't buy the UN-54 because of the plastic cup. Shimano has basically cheaped out on the tapered BB business, and want you to get their latest stuff, which is no better than the previous.

    Here is just one place that has some tapered BB's : http://www.biketoolsetc.com/index.cg.../Taper-Spindle
    The Tange LN39 and 59 are very good. The RPM ones are also good. I wouldn't bother with the YST brand. Sunrace, I don't know.

    What is the frames spacing, 130 or 135mm?

    The singlespeed forum may be able to help you better with chainline setup.


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