New Chainrings for Ultegra Triple

mab bee
mab bee Posts: 196
edited April 2008 in Workshop
I need to replace the outer (52 tooth) chainring on my Ultegra 10sp Triple chainset. I'd like to take the opportunity to reduce the gearing slightly by replacing the 52tooth with a 48tooth and at the same time swapping the inner ring from a 30 to a 26 or possibly 24.

It seems very dificult to be sure exactly what chainrings will be compatible. Will any 48tooth 130BCD outer and 26tooth 76BCD inner work? I dont need to swap the middle ring at the moment, but will that run okay with any size inner and outer ring?

One other option is to swap the whole chainset for an MTB one (probably LX or XT) -- but would that run okay with a 10sp chain and ultegra front Mech?

Cheers

Comments

  • mab bee
    mab bee Posts: 196
    bump!
  • acorn_user
    acorn_user Posts: 1,137
    THe mtb chainset will work, but you may well need a new BB. You might have some trouble with the Ultegra front mech too. There are not many options for that kind of thing. The best option is the IRD Alpina, which is designed for a 48t ring.

    Nice touring chainsets with those ratios include the Stronglight Impact and TA Vega.

    As for shifting, AFAIK Shimano has a set idea about what ratios you will be using. If you go outside of those, shifting will suffer.

    Good luck!
  • mikegibbons
    mikegibbons Posts: 25
    I've just put 48 - 34 - 28 onto my ultegra chainset. Shifting using a standard front triple ultegra is OK but needs a bit of effort. I can't find a dealer in the UK for the IRD Alpina - does anyone know of one? Or ar there any more alternatives?

    Thanks for any replys

    acorn_user wrote:
    THe mtb chainset will work, but you may well need a new BB. You might have some trouble with the Ultegra front mech too. There are not many options for that kind of thing. The best option is the IRD Alpina, which is designed for a 48t ring.

    Nice touring chainsets with those ratios include the Stronglight Impact and TA Vega.

    As for shifting, AFAIK Shimano has a set idea about what ratios you will be using. If you go outside of those, shifting will suffer.

    Good luck!
    Mike Gibbons
    LE > JoG starts 18 Aug 2007
  • mab bee
    mab bee Posts: 196
    Mike,

    How did you fit the 34tooth ring? I thought 38tooth was as small as you could go with the 130BCD setup on a 10sp Ultegra Chainset
  • mikegibbons
    mikegibbons Posts: 25
    Oops - typo, it's a 38
    mab bee wrote:
    Mike,

    How did you fit the 34tooth ring? I thought 38tooth was as small as you could go with the 130BCD setup on a 10sp Ultegra Chainset
    :o
    Mike Gibbons
    LE > JoG starts 18 Aug 2007
  • mab bee
    mab bee Posts: 196
    Just to check Mike, You are running 10 speed aren't you? Only the Shimano website says that the difference between middle and big ring must be at least 13T to prevent the inner part of the front mech from fouling on the middle ring when you change up to the top ring. Looking at my setup (52T/39T big/middle) I can see that would be a problem if the tooth difference was much less than 13T.

    mikegibbons wrote:
    Oops - typo, it's a 38
    mab bee wrote:
    Mike,

    How did you fit the 34tooth ring? I thought 38tooth was as small as you could go with the 130BCD setup on a 10sp Ultegra Chainset
    :o
  • duncan harris
    duncan harris Posts: 4
    The IRD site lists a UK distributor here:

    http://www.interlocracing.com/contactus.html

    United Kingdom Distributor:
    FINE-adc
    http://www.fine-adc.com/
    10 New Well Wynd
    Linlithgow
    West Lothian
    United Kingdom
    EH49 7EW
    +44 (0) 1506 203 978
    E-mail: info@fine-adc.com

    I'm interested in a new bike with similar gearing. Let us know how you get on.
    mikegibbons wrote:
    I've just put 48 - 34 - 28 onto my ultegra chainset. Shifting using a standard front triple ultegra is OK but needs a bit of effort. I can't find a dealer in the UK for the IRD Alpina - does anyone know of one? Or ar there any more alternatives?

    Thanks for any replys
  • mikegibbons
    mikegibbons Posts: 25
    Just shows I should not trust my memory, I've now had a look at the bike, here's what I had on last year on my Roberts Audax:

    9 speed ultegra shifters, front der braze on FD6503, ultagra rear der, TA 50, 39, 28 designated 9 - 10 speed., 12-27 ultegra rear. Shifteed OK but needed to shift to higher trim position (one big push) on small to middle ring shift to make the shift happen. This all worked reliably on Land's End - John O Groats last August

    This year I've upgraded:

    Dura 10 speed shifters, 10 speed cassette 12-27, new chain, all else the same. Chaning is cleaner with no need to overshift on small to middle.

    So I reckon that set up can cope with an 11 difference between middle and top but maybe later front ders have changed.


    duncan harris wrote:
    The IRD site lists a UK distributor here:

    http://www.interlocracing.com/contactus.html

    United Kingdom Distributor:
    FINE-adc
    http://www.fine-adc.com/
    10 New Well Wynd
    Linlithgow
    West Lothian
    United Kingdom
    EH49 7EW
    +44 (0) 1506 203 978
    E-mail: info@fine-adc.com

    I'm interested in a new bike with similar gearing. Let us know how you get on.
    mikegibbons wrote:
    I've just put 48 - 34 - 28 onto my ultegra chainset. Shifting using a standard front triple ultegra is OK but needs a bit of effort. I can't find a dealer in the UK for the IRD Alpina - does anyone know of one? Or ar there any more alternatives?

    Thanks for any replys
    Mike Gibbons
    LE > JoG starts 18 Aug 2007

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