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Smaller chainrings?

Discussion in 'Bicycle Mechanics and Repairs' started by vbc, 22 Apr 2008.

  1. vbc

    vbc Guest

    Location:
    Bristol
    Just thinking of building up my new bike, transferring the 9 speed Ultegra groupset from my old OCR. The chainset is a 30-42-52 triple which I want to down size to a 30-39-50.

    Yes, I could get a new Tiagra chainset but I want to adapt what I have and keep the 167.5mm cranks, so any suggestions for new 39 & 50 9 speed chainrings at Ultegra level?
     
  2. Crackle

    Crackle Pah Staff Member

    Location:
    Wirral
    Hope I've understood the question right but I've just changed chainrings on my own Tiagra chainset with mistakes, so hopefully I can help you avoid the same ones.

    I think I'm right in saying you won't get Shimano rings in 39. So my advice is look at the TA rings. In particular make sure you get a TA middle which has the Shimano profiled ramps on to help chainshift. I didn't and funnily enough it doesn't work :biggrin: Soon to be rectified.

    Using chainrings other than Shimano might slightly alter your shifting effeciency, especially under pressure but the TA seem to be designed to work with Shimano chainsets so hopefully they won't. You also need to have a certain tooth gap to avoid rubbing problems but that combination should be fine. I think it's below an 8 teeth jump which might cause you problems.

    And finally: If you find a TA middle in 38/39 in stock, can you let me know where :biggrin:
     
  3. make sure that the seat tube is the same thickness for your front mech.
     
  4. TA rings are sweeet man. Fishers of Finchley do LOOK branded TA rings which are even sweeeter.
     
  5. OP
    OP
    vbc

    vbc Guest

    Location:
    Bristol
    I've ordered some TA Alize rings from www.dotbike.com. Thanks for your comments.
     
  6. Crackle

    Crackle Pah Staff Member

    Location:
    Wirral

    The 38 is out of stock though :rolleyes:
     
  7. Try Spa Cycles (harrogate) - they have good stocks of TA and Stronglight rings.

    TA are good but Stronglight are just as good and a bit cheaper.
     
  8. TheDoctor

    TheDoctor Man-Machine Staff Member

    Location:
    Stevenage
    Stronglight rings are great. I'm running 48/38/24 on a Sora and the change is as sweet as. The middle has no ramps or nothing, but it still changes like a good'un. :angry: