Advertise on Bikeforums.net



User Tag List

Results 1 to 15 of 15
  1. #1
    The bike plague MightyLegnano's Avatar
    Join Date
    May 2010
    Location
    Greek mountains
    My Bikes
    70's Legnano Road Bike, Late 70's Mercier Road Bike, Ideal Target Mountain Bike and a unicycle
    Posts
    236
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Rear derailleur get jammed in the big cogs of the cassette [SOLVED]

    I have this problem and I can't shift to low gears in the back when I have low gear in front (first sprocket). It seems like the hanger is too short for this cassette or something (although is not).

    Here's the pic with the der stuck in the big cog.




    Any ideas?
    Last edited by MightyLegnano; 04-17-12 at 12:06 PM.

  2. #2
    Senior Member rdtompki's Avatar
    Join Date
    Nov 2008
    Location
    Hollister, CA
    My Bikes
    Volagi, daVinci Joint Venture
    Posts
    3,934
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You've tried to adjust the B-screw? Which RD. Look up RD adjustment on the Park Tools website.
    Rick T
    --------
    Volagi - Triple"ized" and Tubeless
    daVinci Joint Venture

  3. #3
    Senior Member IthaDan's Avatar
    Join Date
    Jan 2012
    Location
    Ithaca, NY
    My Bikes
    Click on the #YOLO
    Posts
    4,648
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)
    B-bolt? That's the one that hits the fin on the hangar.

  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
    25,599
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    Another possibility is you have a freewheel/cassette with a large cog that is beyond the derailleur's capacity. Most derailleurs are rated for a maximum possible cog size and, while that can be stretched a bit, there are limits.

  5. #5
    The bike plague MightyLegnano's Avatar
    Join Date
    May 2010
    Location
    Greek mountains
    My Bikes
    70's Legnano Road Bike, Late 70's Mercier Road Bike, Ideal Target Mountain Bike and a unicycle
    Posts
    236
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I can't find the damn screw on that derailleur. Even the old ones has this?

  6. #6
    The bike plague MightyLegnano's Avatar
    Join Date
    May 2010
    Location
    Greek mountains
    My Bikes
    70's Legnano Road Bike, Late 70's Mercier Road Bike, Ideal Target Mountain Bike and a unicycle
    Posts
    236
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I screw the hanger of the derailleur on an angle so the spring gets more pressure. So for now it seems to work ok. Thanks for your help.

  7. #7
    Senior Member Bill Kapaun's Avatar
    Join Date
    Feb 2007
    Location
    Mid Willamette Valley, Orygun
    My Bikes
    86 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.
    Posts
    7,035
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by MightyLegnano View Post
    I can't find the damn screw on that derailleur. Even the old ones has this?
    The cheaper ones may not have a B screw.
    If you can change the "angle" of the DER, it sounds like you have one of the cheap ones that clamps on with the axle nut.

    Another possibility is the chain is too short???

    Did this problem just occur out of the blue?

    Also the cheaper clamp on type DER's usually are only good for a 28T max cog.

  8. #8
    Senior Member
    Join Date
    Jan 2012
    Location
    Spokane, WA
    My Bikes
    Specialized Sequoia Elite/Motobecane Fantom Cross Team Ti/'85 Trek 520
    Posts
    2,227
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    I have seen this issue when cheap people will use a cheap crappy derailleur on a bike with a derailleur hanger. The cheap derailleur has no stop or b-screw and then as time goes on, the derailleur will then slowly rotate until it finally hits the cassette/freewheel cogs.

    Can you show us a bigger picture of the whole area including the derailleur and how its mounted to the frame? And what kind of bike is it/

  9. #9
    The bike plague MightyLegnano's Avatar
    Join Date
    May 2010
    Location
    Greek mountains
    My Bikes
    70's Legnano Road Bike, Late 70's Mercier Road Bike, Ideal Target Mountain Bike and a unicycle
    Posts
    236
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Bill Kapaun View Post
    The cheaper ones may not have a B screw.
    If you can change the "angle" of the DER, it sounds like you have one of the cheap ones that clamps on with the axle nut.

    Another possibility is the chain is too short???

    Did this problem just occur out of the blue?

    Also the cheaper clamp on type DER's usually are only good for a 28T max cog.
    No, it appeared when I change the cassette with a new one but with the same number of cogs. And the biggest one has 28. Yes it's a very old and cheap one. RD-YT20 is the model. No the chain is ok I think.

    I have seen this issue when cheap people will use a cheap crappy derailleur on a bike with a derailleur hanger.
    Cheap people??
    It's an old Mercier - Special Tour De France
    I don't think it's the problem you describe.

    Two more photos
    http://i43.tinypic.com/24cgkgn.jpg

    http://i39.tinypic.com/246t7nr.jpg

  10. #10
    Senior Member
    Join Date
    Jan 2012
    Location
    Spokane, WA
    My Bikes
    Specialized Sequoia Elite/Motobecane Fantom Cross Team Ti/'85 Trek 520
    Posts
    2,227
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by MightyLegnano View Post
    Cheap people??
    It's an old Mercier - Special Tour De France
    I don't think it's the problem you describe.

    Two more photos
    http://i43.tinypic.com/24cgkgn.jpg

    http://i39.tinypic.com/246t7nr.jpg
    Bingo!

    that is EXACTLY the problem I was referring to. That is a cheap low-end 80's era Shimano early sort of indexing rear derailleur. Cheap and made for Huffys and Murrays.

    See how there is an extra hole in the hanger? That is for a bolt that goes into a cheap Huffy frame that keeps the derailleur clocked right. Without that bolt, the derailleur will eventually rotate and get tangled up again in the cogs.

    Your mercer probably has a real derailleur hanger which is used with a mid range or higher derailleur that has a B screw. there is no b screw on that cheap SIS derailleur.

  11. #11
    The bike plague MightyLegnano's Avatar
    Join Date
    May 2010
    Location
    Greek mountains
    My Bikes
    70's Legnano Road Bike, Late 70's Mercier Road Bike, Ideal Target Mountain Bike and a unicycle
    Posts
    236
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The problem is that the real hanger is broken for some reason.
    Also, the derailleur hits the cogs without any rotation!

    I 've managed to screw the hanger (the one with the hole) with an angle on the derailleur so the spring puts more pressure on it. So the problem solved for now atleast!
    Last edited by MightyLegnano; 04-19-12 at 05:56 AM.

  12. #12
    Senior Member
    Join Date
    Jan 2012
    Location
    Spokane, WA
    My Bikes
    Specialized Sequoia Elite/Motobecane Fantom Cross Team Ti/'85 Trek 520
    Posts
    2,227
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Ouch. Well then that is not a problem I am unsure of solving. I'm pretty sure you can get claw adapter so you can use a better derailleur (your bike deserves a better derailleur) but I'm not sure how it would work.

    I wonder if you can get a new hanger welded back on but would that be too expensive?

  13. #13
    The bike plague MightyLegnano's Avatar
    Join Date
    May 2010
    Location
    Greek mountains
    My Bikes
    70's Legnano Road Bike, Late 70's Mercier Road Bike, Ideal Target Mountain Bike and a unicycle
    Posts
    236
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I'm considering buying something like this: http://www.cambriabike.com/shopexd.asp?ID=133416
    It has already a hanger.

    It's a rare thing to see, a broken hanger. Especially on a road bike. I can imagine the tortures this bike went through from the previous owner.

    I don't think a welded hanger would be expensive, but more of a hassle I'm not very prepared to go through. And this bike is a tough oldman, wouldn't mind rolling with some modifications on its frame ))
    Bicyclosis! Bike hacks, bike adventures and radical ideas >> http://bicycleobsession.wordpress.com

  14. #14
    Senior Member
    Join Date
    Feb 2012
    Location
    SoCal
    My Bikes
    1983 Trek 620, 2010 Roubaix
    Posts
    370
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by bobotech View Post
    I have seen this issue when cheap people...
    Jeez, the guy is just trying to get his bike working. No need to run the guy down...

    -Tom in SoCal

  15. #15
    Senior Member
    Join Date
    Jan 2012
    Location
    Spokane, WA
    My Bikes
    Specialized Sequoia Elite/Motobecane Fantom Cross Team Ti/'85 Trek 520
    Posts
    2,227
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Hendo252 View Post
    Jeez, the guy is just trying to get his bike working. No need to run the guy down...

    -Tom in SoCal
    That was not my intention. I had the same issue on my bike. Someone wanted to get the Univega I bought working as cheap as possible to flip on CL. So they stuck the same derailleur as the OP's (SIS Shimano that is found on lots of Huffys) onto my Univega bypassing the factory derailleur hanger. When i posted about "cheap", i was still annoyed with the guy who was trying to flip a bike for as cheap as possible hence my cheap comment.

Posting Permissions

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