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  1. #1
    Geezer Clyde
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    10-Speed Ultegra Chainring question

    I have an Ultegra 5-bolt Triple Crank with a 10 speed cassette, and would like to replace the small 30T chainring with something in the neighborhood of a 26T ring.

    Anybody have any experience with this that could recommend a vendor for the chainring?
    Bicycle Commuting ROCKS!

  2. #2
    Elitist Troglodyte DMF's Avatar
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    You need one with a 92mm BCD. I'm not sure anyone makes one...

    What's your cassette range?
    Stupidity got us into this mess - why can't it get us out?

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  3. #3
    Low car diet JiveTurkey's Avatar
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    Only one generation of Dura Ace used the 92mm BCD inner ring, which was only available in 30T. More likely the OP needs a 74mm BCD, such as: http://sheldonbrown.com/harris/chainrings/74.html#26
    Quote Originally Posted by slopvehicle View Post
    Not wearing a helmet makes me more aware of my surroundings. I find myself anticipating the hardness of concrete 50 or 100 feet in front of me, it's almost a zen-like connection between my face and the pavement.

  4. #4
    Elitist Troglodyte DMF's Avatar
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    Do a little research before posting.

    http://techdocs.shimano.com/media/te...9830676705.pdf
    Stupidity got us into this mess - why can't it get us out?

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  5. #5
    Low car diet JiveTurkey's Avatar
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    Didn't realize the 6703 Ultegra also used the odd-ball BCD. However, the 6603 model used 74mm and the 6600-series of Ultegra components were also 10-speed. OP: can you clear up which you have?

    [Edit. Got rid of my options because davidad's is much better.]
    Last edited by JiveTurkey; 11-21-09 at 12:43 AM.
    Quote Originally Posted by slopvehicle View Post
    Not wearing a helmet makes me more aware of my surroundings. I find myself anticipating the hardness of concrete 50 or 100 feet in front of me, it's almost a zen-like connection between my face and the pavement.

  6. #6
    cab horn
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    26 lol
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  7. #7
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    If you have the ****mano 6703 with the 92mm small ring you will have to get a TA adapter middle ring that will allow you to use 74mm BCD rings. May as well go with a 24t just in case you ever need it.
    The 6603 uses a conventional 74 BCD ring.

  8. #8
    Senior Member Jed19's Avatar
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    I have the Ultegra 6603. Does that mean a 74mm BCD/26teeth specified for 9-Speed will work for me?
    Regards,

    Jed

  9. #9
    Low car diet JiveTurkey's Avatar
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    Quote Originally Posted by LUCAS View Post
    I have the Ultegra 6603. Does that mean a 74mm BCD/26teeth specified for 9-Speed will work for me?
    Some would disagree, but many would say it is okay to mix specified speeds of chainrings.
    Quote Originally Posted by slopvehicle View Post
    Not wearing a helmet makes me more aware of my surroundings. I find myself anticipating the hardness of concrete 50 or 100 feet in front of me, it's almost a zen-like connection between my face and the pavement.

  10. #10
    Senior Member
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    Quote Originally Posted by LUCAS View Post
    I have the Ultegra 6603. Does that mean a 74mm BCD/26teeth specified for 9-Speed will work for me?
    Yes, it will work. I've made the exact same change on numerous 7,8 and 9-speed Shimano triple cranks and even on a 10-speed Campy triple crank and they all work well. Generally, I've used generic 74 mm bcd rings as granny rings aren't pinned, ramped, etc the way the larger chainrings are.

    I would recommend adding a "chain watcher" to assure the chain won't spill to the inside on an emergency shift under load. Shifts to the granny ring are often done in a real hurry after you realize the hill is a LOT steeper than you thought.

  11. #11
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    The 24t and larger will work.
    The shift up to the middle ring won't be as smooth, but it is still easily done.

  12. #12
    Elitist Troglodyte DMF's Avatar
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    Quote Originally Posted by LUCAS View Post
    I have the Ultegra 6603. Does that mean a 74mm BCD/26teeth specified for 9-Speed will work for me?
    Yes.
    Stupidity got us into this mess - why can't it get us out?

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