Advertise on Bikeforums.net



User Tag List

Results 1 to 7 of 7
  1. #1
    Senior Member
    Join Date
    Jan 2008
    Location
    (BOS + PVD)/2
    Posts
    283
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Front derailleur for compact crank?

    I have a Jake the Snake setup as a commuting bike. But I went "cheap" and put mostly hand-me-down junk that I had on it, and so it doesn't really work well. My road bike is 10-speed DuraAce, and I want that feel.

    The primary problem (I think) is that the combination of compact crank and Shimano 105 triple front derailleur (taken off a tandem, no less) don't get along with the 9-speed cassette. I just can't set it up to not have the chain hitting the derailleur on most gears, particularly on the small chainring.

    So, is there a front derailleur that is designed for this sort of situation? I am relatively unfamiliar with compact cranks. For reference, the shifters are Shimano 105, also triple from the tandem.

    As a side note, I want to go to 10 speed on this for wheel compatibility (although I know I can just change cassettes), but I don't think that should affect the FD choice. Tell me if I am wrong on that.

  2. #2
    Senior Member
    Join Date
    Dec 2006
    Location
    Northern VT
    My Bikes
    recumbent & upright
    Posts
    1,545
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Consider a 1x9 set up ?
    It is usually easy to scrounge up a 39 t chain ring and an 11-34 cassette.
    This combination is pragmatic and reliable for a commuter.
    ride long & prosper

  3. #3
    Team Water Andy_K's Avatar
    Join Date
    Jan 2008
    Location
    Beaverton, OR
    My Bikes
    2013 Kona Jake, 2008 Kona Major Jake, 2013 Kona Jake the Snake, 1999 Kona Muni Mula, 2012 Ridley Excalibur, 2008 Surly Long Haul Trucker
    Posts
    6,795
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The FSA Energy front derailleur is designed for compact cranks.

  4. #4
    RT
    RT is offline
    The Weird Beard RT's Avatar
    Join Date
    May 2005
    Location
    COS
    Posts
    8,525
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    martianone has a great idea. I am building the MTB version of your proposed bike. I didn't want to mess with the FD, and am using a Deore RD. I settled on a 44t ring up front and an 11-32 Forte ($17.95) cassette. Build will be finished as soon as wheels arrive next week and will post pics, but this setup will make an awesome commuter.

  5. #5
    Senior Member
    Join Date
    Jan 2008
    Location
    (BOS + PVD)/2
    Posts
    283
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Just to clarify, I think a dedicated commuter is a nice idea, and even considered going to a single chainring, but this bike is also my winter training bike, and may be used for cyclocross (I haven't done it yet, but it was part of my plan for getting this bike and putting a compact crank on it). So I am looking for something that is very "normal", I just want to be able to use all the gears without sounding like a coffee grinder. I have read elsewhere that there really isn't a need for a compact-specific FD, but I am pretty sure this 105 triple FD is a big part of the problem. So, would I see a difference between an FSA Energy FD and some random Ultregra double FD? It seems like the trick is where the cage is relative to the small chainring that is the difference.

    Or maybe the real problem is the 105 triple shifter, which never seemed to have the right "trim" points for the triple, and certainly doesn't seem right now.

    My goal is to be able to get the rightmost 6 cogs when on the big chainring with the FD in the outer most position. The inner 3 cogs should be usable (not hitting the cage) with one trim-step down. I want the same with the small ring - the left six cogs usable at the inner most cage position, with trim allowing me to get to the 3 outermost. It doesn't seem like much to ask, but I have come to the conclusion that it is impossible with the parts I have now.

  6. #6
    RT
    RT is offline
    The Weird Beard RT's Avatar
    Join Date
    May 2005
    Location
    COS
    Posts
    8,525
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Sounds like an excellent reason to buy something new for your bike :-D FDs are cheap, and a triple FD with a compact double sounds like trouble - maybe search the mechanics forum. I assume the 105 triple is 50-39-30? If so, get a new double FD, a 36t or 34t inside ring, and just remove the 30t ring. I would hope that a 10 speed 105 34t would work for your 9 speed setup, but mechanics would know that for sure. In my experience, if you adjust your components, even if they're lower end Sora and below, you'll have a good experience. My 8 speed commuter is using Tourney-grade stuff and runs just fine only because it doesn't give me reason to replace it.

  7. #7
    Team Water Andy_K's Avatar
    Join Date
    Jan 2008
    Location
    Beaverton, OR
    My Bikes
    2013 Kona Jake, 2008 Kona Major Jake, 2013 Kona Jake the Snake, 1999 Kona Muni Mula, 2012 Ridley Excalibur, 2008 Surly Long Haul Trucker
    Posts
    6,795
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The difference in cage size between the Tiagra triple that I started out with and the Energy double that I switched to is huge. I don't have a normal Ultegra double FD, so I can't say, but I suspect that would work.

Posting Permissions

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