Advertise on Bikeforums.net



User Tag List

Results 1 to 6 of 6
  1. #1
    Senior Member
    Join Date
    Mar 2008
    Posts
    4,216
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Front derailer: pros and cons of seat tube mount vs BB mount?

    Hi all,
    Well, the headline says it all really. Am looking to buy a new (MTB front) derailer, and suddenly realized there was another option I hadn't considered. Never used a BB mount before.

    The BB mount seems somewhat neater, but I imagine alignment might be trickier.
    Seat tube mount is an old aquaintance; I'm not worried about any surprises there. It's certainly worked well enough before.

    Any preferences, tips and pointers, let me know.

    Cheers,

  2. #2
    Senior Member CACycling's Avatar
    Join Date
    Feb 2008
    Location
    Oxnard, CA
    My Bikes
    '08 Fuji Roubaix RC; '07 Schwinn Le Tour GS; '92 Diamond Back Ascent EX
    Posts
    4,441
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    BB mounted FDs are typically used where seat tube mounting is not an option (such as on 'bents). Not sure why you'd use one if seat tube is an option.

  3. #3
    Senior Member
    Join Date
    Mar 2008
    Posts
    4,216
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by CACycling View Post
    Not sure why you'd use one if seat tube is an option.
    Neither am I. But having the option open increases the number of possible candidates when bargain hunting...

  4. #4
    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
    25,576
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    Bottom bracket mounts are usually limited to suspension MTBs and other bikes where the seat tube is not round and has no braze-on mounting tab. Also, check to be sure the bb mounted derailleur has the cable pull from the correct direction as many MTB's use a top pull arrangement and that's unusual on road bikes.

    Me? If a seat tube clamp-on or a braze-on adapter fits, that's what I'd use.

  5. #5
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    506
    Mentioned
    31 Post(s)
    Tagged
    0 Thread(s)
    Then you have to consider the Big ring size you want to run.

    2 schemes decide that for you.. BB mount ,
    and where a braze on mount is fitted on the seat tube.

  6. #6
    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
    25,576
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by fietsbob View Post
    Then you have to consider the Big ring size you want to run.
    Good point. BB mounts usually assume a MTB crank and a 42 or 44T big ring and you can't adjust the derailleur high enough for a typical road 52 or 53T chainring

Posting Permissions

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