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  1. #1
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    Need a road crankset on a mountain bike frame.

    Hello and I hope you can help me out. I have an old mountain bike that has been converted for road use. Have the drop bars and road gearing. But this bike has 8 cogs in the back and a triple up front.

    I wanted to convert this to a 10-speed triple. I have replaced the cogs, both the front and rear derailleurs, chain and the shifters were replaced with Shimano 10-speed bar end shifters.

    I have not changed the cranks that are Sugino XD with Salsa chainrings (28-38-50). Since this crank is an 8-speed, the 10-speed chain gets stuck between the rings. Is there a fix for this or will I just need to get a 10-speed crank?

    If I need a new crank set, I need help in deciding what crank and bottom bracket to get. I measured the BB and it is 68 mm. Will I be able to get a road crank on this bike, looking for a 50-39-30? (Note, although I currently have a 50 tooth chainring, this is with a square taper bottom bracket, and although I do not remember the spindle length, it may be longer than normal to fit the 50 tooth ring).
    Any ideas?

    Thanks,
    Mark

  2. #2
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    The only question I can answer is the last one regarding a 50-39-30 on the ATB.

    The chainstay curve and shape may not allow larger rings, and I wouldn't recommend changing the chainline to make them clear the chainstay.

    You could try changing just the chainrings and see if that cures your problem. The ring profiles may result in closer ring spacing and stop the dropped chain.

  3. #3
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    Thanks for the idea. I had casually looked for 110 x 74 BCD of the rings I was interested, and had a hard time finding a good selection. After reading your post, I found TA Zephyr rings that may work. Worth a try, thanks again.

  4. #4
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    Quote Originally Posted by Deering View Post
    I have not changed the cranks that are Sugino XD with Salsa chainrings (28-38-50). Since this crank is an 8-speed, the 10-speed chain gets stuck between the rings. Is there a fix for this or will I just need to get a 10-speed crank?
    I am surprised to hear this. I converted an older 8-speed touring bike into a 10-speed and am currently using a square taper Sugino XD600 26/36/46 triple crankset (technically an "8-speed" in marketingland). I don't have any problems with it. It shifts beautifully.
    "With bicycles in particular, you need to separate between what's merely true and what's important."-- DCGriz, RBR.

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  5. #5
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    Quote Originally Posted by Lombard View Post
    I am surprised to hear this. I converted an older 8-speed touring bike into a 10-speed and am currently using a square taper Sugino XD600 26/36/46 triple crankset (technically an "8-speed" in marketingland). I don't have any problems with it. It shifts beautifully.
    Yea I am a bit bummed about this as it seems like everybody and their mother said it would work. I do recall when I first installed these chainrings (Salsa) that I needed longer chainring bolts to fit. So maybe these rings are just thicker than normal causing a slightly larger gap. But running 8-speed wasn't a problem.
    With the 10-speed chain, on the workstand it shifts beautifully, just on the test ride with pressure on the pedals did it get jammed between the middle and small ring.

    As I look to just replace the chainrings, I was looking at the TA Zephyr rings and then saw on Peter White's website that TA rings don't seem to work on Sugino cranks. But found on the Jenson website that they have Sugino rings. They are for 9-speed, but I might try those and keep it all Sugino.

    Will keep you all posted, thanks to everybody for the input and help.

  6. #6
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    Quote Originally Posted by Deering View Post
    As I look to just replace the chainrings, I was looking at the TA Zephyr rings and then saw on Peter White's website that TA rings don't seem to work on Sugino cranks. But found on the Jenson website that they have Sugino rings. They are for 9-speed, but I might try those and keep it all Sugino.

    Will keep you all posted, thanks to everybody for the input and help.
    I'm pretty sure this will work.
    "With bicycles in particular, you need to separate between what's merely true and what's important."-- DCGriz, RBR.

    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein



  7. #7
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    Since you can already fit a 50 on there, I think you're on your way to success.

    FWIW, I converted an old 26" frame to a commuter gravel bike and there wasn't any way I could get a 50t compact crankset on there, so I went with a trekking crankset from Shimano, it's essentially their mtb triple cranksets with a 48 on it, which is as big as my frame will manage.

    Like this, although mine is 9sp.

    https://bike.shimano.com/en-EU/produ.../FC-T6010.html

  8. #8
    Huge in Japan
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    I'm not intimate with your set-up but is your set-up one where the assembled chainring spacing is a function of the chainring mounting faces of your crank (distance between mounting faces)? I am guessing/ wondering if, based on the compatibility conflict that you ran into, that Sugino might have some unique geometry?

    Dunno, just throwing it out there and asking at the same time since you said you want to stick to the same crank.
    Last edited by craiger_ny; 05-01-2018 at 04:21 PM.
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  9. #9
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    Quote Originally Posted by craiger_ny View Post
    I'm not intimate with your set-up but is your set-up one where the assembled chainring spacing is a function of the chainring mounting faces of your crank (distance between mounting faces)? I am guessing/ wondering if, based on the compatibility conflict that you ran into, that Sugino might have some unique geometry?

    Dunno, just throwing it out there and asking at the same time since you said you want to stick to the same crank.
    It looks like there may be an issue with the Sugino crank. On the Peter White website he discusses the Sugino crank has a fixed spacer that puts the TA Zephyr small ring too far inward. This may be one of the problems as the chain got stuck between the small and middle ring.
    As Harryman had done, I was also thinking about just getting new cranks. Would like a bit higher gearing, but this a commuting work horse, so having a 26-36-48 would be fine for my needs.
    But still entertaining the idea just replacing the cranks. I emailed Jenson regarding their 9-speed rings and they said it won't work as they are too wide for the 10-speed. Right now, I am tempted to try the Sugino rings anyway.

  10. #10
    Huge in Japan
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    Don't know what your cassette is but if it is 11-XX then 48/11 is pretty tall for a commuter, can't imagine needing taller.
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  11. #11
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    Agreed a 48x11 is about as high as I should go. Good point.

  12. #12
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    How old an MTB frame is this? 68mm threaded on an MTB is a bit odd, I'd expect to find 73mm.
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  13. #13
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    Its a KHS Alite 500. Purchased in 1997.

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