Oh crap. Did I order the wrong part?- Mtbr.com
Results 1 to 6 of 6
  1. #1
    mtbr member
    Reputation:
    Join Date
    Jun 2012
    Posts
    896

    Oh crap. Did I order the wrong part?

    I ordered the below but I intend to use an Ultegra cx70 front derailleur and a 105 rear derailleur. Will these shifters really not work with that front (and rear?) derailleur?


    And why the $#@! is Shimano being so screwy with their parts compatibility lately?


    Shimano Dura-Ace 7900 BS79 Bar End Shifter

    Bar-end Control (Bar-Con) shifters for road drop or aero type bars
    Rear shifter convertible between index and friction action (BS79 shifters only compatible with Dura-Ace 7900 front derailleur due to revised cable pull actuation)
    Includes cables and housing
    weight: 165g
    color: grey/silver
    speed: 2x10sp
    model: Dura-Ace BS79

  2. #2
    weirdo
    Reputation: rodar y rodar's Avatar
    Join Date
    Jul 2006
    Posts
    6,223
    I`m pretty sure you`re good as long as you have a 10s rear cluster, but that is kind of weird. Friction shifters usually don`t care what they shift, but ya never know. That model is apparently the new ones that don`t have a friction mode for the rear though, so I don`t understand why they still claim dual mode in the description. I don`t see 7900 on the current Shimano website, but the tech that I found just says "recomended" for DA front derailler. Here`s a thread that popped up concerning the same issue:

    Anyone successfully using Dura Ace SL-BS79 Shifters with Ultegra 6700 Front derailleur: Triathlon Forum: Slowtwitch Forums

  3. #3
    mtbr member
    Reputation:
    Join Date
    May 2011
    Posts
    1,025
    The main concern is if you can't pull enough cable to make the derailleur move far enough. I'm guessing that there's a good chance you can clamp the cable in the front der in a manner other than intended that will allow it to work. This will work if the dura-ace derailleur is supposed to be paired with a shifter with low travel, high tension cable movement.

    More likely it will just be hard to pull the shift lever; dura-ace has been moving towards high travel low tension cables ( at least for brakes), so my guess is that worst case scenario is that you have to pull the left barcon lever a little harder than usual and not as far to accomplish the shift.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Jun 2012
    Posts
    896
    Apparently the front is friction only while the rear is now INDEXED ONLY. Which is weird. How are the tourist to go to 10speed?

    Supposed to be compatible with everything road though.

  5. #5
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,236
    Quote Originally Posted by aBicycle View Post
    Apparently the front is friction only while the rear is now INDEXED ONLY. Which is weird. How are the tourist to go to 10speed?

    Supposed to be compatible with everything road though.
    You use a different front shifter for a triple, if the M79 is indeed 2x only.

    You sure have a lot of questions for somebody that has been riding for 92 years.
    Last edited by shiggy; 08-03-2012 at 05:43 PM.
    mtbtires.com
    The trouble with common sense is it is no longer common

  6. #6
    mtbr member
    Reputation:
    Join Date
    Jun 2012
    Posts
    896
    I think it can do a triple actually.

    And it's all these damned new fangled parts! I mean, how many ****ing different standard and ways of doing things does there need to be??!?!??!?!

Members who have read this thread: 0

Posting Permissions

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

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2020 VerticalScope Inc. All rights reserved.