Advertise on Bikeforums.net



User Tag List

Results 1 to 5 of 5
  1. #1
    Newbie
    Join Date
    Jan 2010
    Posts
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Repeated broken Derailleur- Please Help!

    A happy new year to all,

    i wish i could continue on the festive cheer but i have a repeated problem with my derailleur and would love someone with more knowledge to have some input.

    When changing gear one day i noticed there was a problem with my derailleur.......the fact was the upper of the two cogs just wasnt there! The cog had completely dropped off the bike whist shifting! In my disappointed state i went to a repair shop (which i have to admit uses second hand parts) to fix it and the problem seemed fine but alas, after about 15 miles, the very same thing happened.

    I understand that its is very difficult to diagnose such a problem when not with the bike, but i am wondering if anyone knows of any common problems which may put undue pressure on this part which then causes it to disintegrate!

    Is it time for a new bike you think? Or are such things repairable without changing the derailleur, free wheel, chain etc.

    Any advice would be appreciated.

    Thanks

  2. #2
    Senior Member Retro Grouch's Avatar
    Join Date
    Feb 2004
    Location
    St Peters, Missouri
    My Bikes
    Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
    Posts
    23,105
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If I had to guess I'd say somehow the cage was damaged and the little bolt that holds in the upper jockey pulley keeps coming out. If it was my bike, I'd replace the whole rear derailleur. A used rear derailleur is usually an OK bet provided it has adequate capacities. Rear derailleurs usually take a long time to wear out.

  3. #3
    Senior Member Steev's Avatar
    Join Date
    Jul 2005
    Location
    Backwoods of Ontario
    Posts
    2,104
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Maybe the "B" limit screw is missing and the jockey wheel is mashing into the larger cogs.

  4. #4
    Newbie
    Join Date
    Jan 2010
    Posts
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    No, i am pretty sure the jockey wheel wasnt moving onto the cogs. I did notice there was maybe more 'play' in the jockey wheel previously so maybe the first person who replied might be correct in saying the cage was damaged!

    Thanks guys.

    PS: Keep the ideas coming!

  5. #5
    Bianchi Goddess Bianchigirll's Avatar
    Join Date
    Apr 2009
    Location
    Camp Hill, PA
    My Bikes
    Too many to list here check my signature.
    Posts
    18,997
    Mentioned
    4 Post(s)
    Tagged
    1 Thread(s)
    go to a good shop and have a new rear derailleur put on. it is possible since you have lost atleast two upper pulleys the threading is worn or stripped. since a common way to install a new rear derailleur (without a new chain) is to remove one of the pulleys, normally (atleast for me) the upper one. just politely ask them to ensure the bolt is tight and perhaps a dash of loctite. modern front derailleurs are very accurate devices and the days grabbing a used shimano lower pulley and making it work on the top are long gone.
    Bianchis '87 Sport SX, '90 Proto (2), '91 Boarala 'cross, '93 Project 3, '88 Trofeo, '86 Volpe, '89 Axis, '79 Mixte, '99 Mega Pro XL Ti, '97 Ti Megatube, , '90 something Vento 603,

    Others but still loved,; '80 RIGI, '80 Batavus Professional, '87 Cornelo, '86 Bertoni (sold), '09 Motobecane SS, '98 Hetchins M.O., '09 K2 Mainframe, '89 Trek 2000, '?? Jane Doe (still on the drawing board), '90ish Haro Escape

Posting Permissions

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