Advertise on Bikeforums.net



User Tag List

Results 1 to 3 of 3
  1. #1
    Junior Member
    Join Date
    Feb 2006
    Posts
    17
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Choosing a front derailleur

    I am upgrading my front derailleur. I am a little confused about what will work. I am running a 48-38-28 chainring. I have a brand new 105. I believe it is designed for a 52 tooth ring. Will it work or do I need something that will fit the 48?

  2. #2
    Senior Member
    Join Date
    Aug 2005
    Location
    Pittsburgh, PA
    My Bikes
    '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
    Posts
    25,260
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    The 105 triple fd is designed for optimum performance with a 52T big ring but will work fine with a 48. Install it and enjoy. Be sure to install the derailleur low enough so the chainring clearance is correct.

    In fact, my son's old Trek 1220 came with an RSX crank and 46-36-26 chainrings and an RX-100 triple front derailleur (a 105 duplicate but with a bit less finish). The RX-100 was also intended for a 52T ring but shifted the 46 very nicely.

  3. #3
    Senior Member Matt Gaunt's Avatar
    Join Date
    Oct 2004
    Location
    London, UK
    Posts
    2,214
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Yeah it will be fine. The only reason Shimano recommend certain chainring sizes for their mechs is to optimise the contact area to follow the line of the ring.

    This has little or no effect on smaller rings than those recommended sizes when the difference is only 4 teeth or so.
    Matt
    2010 Kinesis Decade Convert2 Alloy fixie, Miche, Sora Pics soon...
    2008 Kinesis RC2 Scandium/Carbon Road, Ultegra, Ksyrium Elites Pics
    2007 Kinesis Pha5e Scandium hardtail, XT, Revelations, Rockets, M4s, Mavics Pics
    2005 Kinesis RC Scandium/Carbon Road, Ultegra, Ksyrium SLs Pics
    1996 Raleigh Max Steel, Deore XT, SRAM Attack shifters, homemade wheels Pics

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •