Advertise on Bikeforums.net



User Tag List

Results 1 to 21 of 21
  1. #1
    Senior Member
    Join Date
    Dec 2009
    Posts
    771
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    When limit screws don't work what do I do?

    I have Ultegra derailers - front that doesn't move low or high, and rear - only moves on the high screw.

    What do I do to get 'em working again?

    Also, I have tried adjusting limits on a Tourney derailer, I think it was, and that showed no movement at all on either limit screw. Is this par for the course with cheaper derailers, or should they be working, too?

  2. #2
    For The Fun of It
    Join Date
    May 2007
    Location
    Louisissippi Coast
    My Bikes
    Specialized Tarmac Expert, Giant XTC, Home built commuter on a Schwinn Supersport GS frame
    Posts
    1,464
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I don't know that I have ever seen a limit screw failure. Have you ever successfully adjusted limit screws. If you don't have much experience with it, read Park Tools and Sheldon Browns instructions. I am marginally experienced and still lean on their words. They never fail me.

  3. #3
    Senior Member
    Join Date
    Apr 2006
    Posts
    2,138
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Limit screws only adjust how far the derailleur can move right to left on the bike. They will only show movement if the derailer is at the limit. They do not adjust or fine tune any other part of the other shifting. They are basicall just stops. Roger

  4. #4
    Senior Member
    Join Date
    Sep 2010
    Posts
    2,580
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    I'd suggest that you review some articles on derailleur adjustment and familiarize yourself with what needs to be done. Follow the instructions from the beginning and do not skip any steps. Here are a couple to get you started:

    http://www.parktool.com/blog/repair-...nts-derailleur
    http://www.parktool.com/blog/repair-...ur-adjustments

  5. #5
    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
    23,583
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by dsbrantjr View Post
    I'd suggest that you review some articles on derailleur adjustment and familiarize yourself with what needs to be done. Follow the instructions from the beginning and do not skip any steps. Here are a couple to get you started:

    http://www.parktool.com/blog/repair-...nts-derailleur
    http://www.parktool.com/blog/repair-...ur-adjustments
    That's what I think too. Limit screws, once set correctly, seldom need to be readjusted.

  6. #6
    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
    6,755
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    They are LIMIT screws.
    Their sole function is to LIMIT how far the DER's move.

    IF you use them to "PUSH" the DER's, you are going to likely wear out the threads in the DER's VERY prematurely, because they aren't designed for that.
    Sounds like you may have already done that?

  7. #7
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    19,888
    Mentioned
    31 Post(s)
    Tagged
    1 Thread(s)
    Imagine either derailleur as a car parallel parked between two others on a hill.

    The two cars are like limit screws. They determine the length of the space you have to maneuver in, and can be mover to give you more or less range of travel. But moving them won't move your car. You have to do that yourself. You can put your car anyplace between either car, and if you release the brake your car will roll back until it touches the lower car.

    The derailleurs are the same, the cable sets their position within the working range according to the lever position, and when the cable is slackened the derailleur (not a car anymore) will settle against the return spring limit (usually outer on the rear and inner on the front). When the cable is pulled all the way tight the derailleur will stop against the upper limit.

    In most systems the return spring limit is used to set that gear position, (inner front, outer rear) with the lever detents (clicks) setting the position in all the others. In some cases the high position is full up against the upper limit, in others, just shy of it allowing a bit of overshift which then settles off the limit.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  8. #8
    For The Fun of It
    Join Date
    May 2007
    Location
    Louisissippi Coast
    My Bikes
    Specialized Tarmac Expert, Giant XTC, Home built commuter on a Schwinn Supersport GS frame
    Posts
    1,464
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    Imagine either derailleur as a car parallel parked between two others on a hill.

    The two cars are like limit screws. They determine the length of the space you have to maneuver in, and can be mover to give you more or less range of travel. But moving them won't move your car. You have to do that yourself. You can put your car anyplace between either car, and if you release the brake your car will roll back until it touches the lower car.

    The derailleurs are the same, the cable sets their position within the working range according to the lever position, and when the cable is slackened the derailleur (not a car anymore) will settle against the return spring limit (usually outer on the rear and inner on the front). When the cable is pulled all the way tight the derailleur will stop against the upper limit.

    In most systems the return spring limit is used to set that gear position, (inner front, outer rear) with the lever detents (clicks) setting the position in all the others. In some cases the high position is full up against the upper limit, in others, just shy of it allowing a bit of overshift which then settles off the limit.
    You are perhaps one of the most helpful people on any of many forums I frequent. I really appreciate your contributions and have learned quite a bit from you. Thanks.

  9. #9
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    19,888
    Mentioned
    31 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by Paul Barnard View Post
    You are perhaps one of the most helpful people on any of many forums I frequent. I really appreciate your contributions and have learned quite a bit from you. Thanks.
    No applause is needed ----- Just throw money!.

    Thanks. You might read this, good words I try to live by.

    The Bridge Builder
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  10. #10
    Senior Member Homebrew01's Avatar
    Join Date
    Jul 2004
    Location
    Ffld Cnty Connecticut
    My Bikes
    Old Steelies I made, Old Cannondales
    Posts
    15,207
    Mentioned
    6 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by Paul Barnard View Post
    You are perhaps one of the most helpful people on any of many forums I frequent. I really appreciate your contributions and have learned quite a bit from you. Thanks.
    Correct. I often enter a thread to give an answer, but notice FBinNY has replied already, so not much left to say.
    Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike

  11. #11
    Senior Member
    Join Date
    Dec 2009
    Posts
    771
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    What is happening is:
    I bought the bike used, and was trying to stop the chain from dropping off the hi and low ends of the rear cogs when shifting. I adjusted the hi screw on rear derailer, and that moved the pulley in line with the cog perfectly. Problem solved on that end.
    But the low screw doesn't seem to do anything.
    Same on hi and Low with the front derailer. The gap between the edge of the cage on either side of the rings is big and I was trying to fine tune it, but the screws don't seem to move anything when turned in either direction.

  12. #12
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    19,888
    Mentioned
    31 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by Homebrew01 View Post
    Correct. I often enter a thread to give an answer, but notice FBinNY has replied already, so not much left to say.
    The converse is also true. In this spirit I have a short list of folks who's posts I respect highly.

    They include (but aren't limited to) Hillrider, MechBgon, mrrabbit, Homebrew and Retro Grouch, We don't always agree, but that doesn't affect the respect I have for these guys.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  13. #13
    Guest
    Join Date
    Jul 2008
    Location
    Grid Reference, SK
    My Bikes
    I never learned to ride a bike. It is my deepest shame.
    Posts
    3,769
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The only possibility I can think of is that the original limit screws were removed and replaced with shorter ones - perhaps to save weight , or maybe someone ground the stops off the inside of the derailleur body (unlikely)

    I think a more likely explanation is you are not adjusting what you think you are- either using the wrong screw, not turning it the right way, or not turning it in far enough. The function of limit screws is very simple and if you look inside the derailleur body you can see what they are doing when they come into play.

  14. #14
    Senior Member Homebrew01's Avatar
    Join Date
    Jul 2004
    Location
    Ffld Cnty Connecticut
    My Bikes
    Old Steelies I made, Old Cannondales
    Posts
    15,207
    Mentioned
    6 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by lungimsam View Post
    What is happening is:
    I bought the bike used, and was trying to stop the chain from dropping off the hi and low ends of the rear cogs when shifting. I adjusted the hi screw on rear derailer, and that moved the pulley in line with the cog perfectly. Problem solved on that end.
    But the low screw doesn't seem to do anything.
    Same on hi and Low with the front derailer. The gap between the edge of the cage on either side of the rings is big and I was trying to fine tune it, but the screws don't seem to move anything when turned in either direction.
    You shouldn't really see anything move while adjusting the screw. The effect is that when you shift, the derailleur will now move more (or less) depending on which way you turned the screw.
    Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike

  15. #15
    Senior Member
    Join Date
    Dec 2009
    Posts
    771
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Homebrew01 View Post
    You shouldn't really see anything move while adjusting the screw. The effect is that when you shift, the derailleur will now move more (or less) depending on which way you turned the screw.
    As far as I know, you should be able to see movement so that you can line up the pulley with the inner or outer cog, whichever limit you are adjusting for.
    I could see the rear derailer pulley moving with every turn of the "H" screw that worked, so that I could line it up easily with the cog. I can turn the other three (the "L" on the rear derailer, and the "h" and "L" on the front derailer) in any direction down or back, with no movement.
    Last edited by lungimsam; 08-04-12 at 01:26 PM.

  16. #16
    For The Fun of It
    Join Date
    May 2007
    Location
    Louisissippi Coast
    My Bikes
    Specialized Tarmac Expert, Giant XTC, Home built commuter on a Schwinn Supersport GS frame
    Posts
    1,464
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    Beautiful!

  17. #17
    Senior Member
    Join Date
    Dec 2009
    Posts
    771
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by LarDasse74 View Post
    The only possibility I can think of is that the original limit screws were removed and replaced with shorter ones - perhaps to save weight , or maybe someone ground the stops off the inside of the derailleur body (unlikely)

    I think a more likely explanation is you are not adjusting what you think you are- either using the wrong screw, not turning it the right way, or not turning it in far enough. The function of limit screws is very simple and if you look inside the derailleur body you can see what they are doing when they come into play.
    I will try to look inside to see if the screws are contacting anything.

  18. #18
    Senior Member Homebrew01's Avatar
    Join Date
    Jul 2004
    Location
    Ffld Cnty Connecticut
    My Bikes
    Old Steelies I made, Old Cannondales
    Posts
    15,207
    Mentioned
    6 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by lungimsam View Post
    As far as I know, you should be able to see movement so that you can line up the pulley with the inner or outer cog, whichever limit you are adjusting for.
    I could see the rear derailer pulley moving with every turn of the "H" screw that worked, so that I could line it up easily with the cog. I can turn the other three (the "L" on the rear derailer, and the "h" and "L" on the front derailer) in any direction down or back, with no movement.
    In that instance, you saw movement because the 'H' screw was touching the tab on the RD and forcing it inward. If the screw is not contacting the tab when you turn it, or you are turning counter-clockwise to allow more movement, it won't move the derailleur because the screw is going away from the tab. I'm not a fan of having contact and forcing the derailleur to move. I prefer to turn the limit screw while not in contact, test the shifting, and repeat until it's good.
    Last edited by Homebrew01; 08-04-12 at 01:41 PM.
    Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike

  19. #19
    Senior Member
    Join Date
    Dec 2009
    Posts
    771
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Homebrew01 View Post
    In that instance, you saw movement because the 'H' screw was touching the tab on the RD and forcing it inward. If the screw is not contacting the tab when you turn it, or you are turning counter-clockwise to allow more movement, it won't move the derailleur because the screw is going away from the tab. I'm not a fan of having contact and forcing the derailleur to move. I prefer to turn the limit screw while not in contact, test the shifting, and repeat until it's good.
    Ah, OK, I see what you mean now.
    All this helps me to understand how these things work, so I can know what I am doing better.
    Thanks.

  20. #20
    Senior Member
    Join Date
    Sep 2010
    Posts
    2,580
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    If you use the Park Tool procedure recommended above, you do not use the rear limit screws to "line up" the chain and pulleys, but to adjust them just loosely enough to allow for correct shifting function and no more. Visual alignment is irrelevant and can be misleading.

    Another erromeous concept is that the barrel adjusters change the shift wire tension. This is incorrect; the tension is set (almost entirely) by the derailleur return spring and the adjusters change the effective wire length by changing the housing length thereby moving the derailleur position relative to a given shifter position.

  21. #21
    Senior Member vredstein's Avatar
    Join Date
    Aug 2008
    Location
    Tucson, Arizona
    My Bikes
    '02 Lemond Buenos Aires, '98 Fuji Touring w/ Shimano Nexus premium, '06 Jamis Nova 853 cross frame set up as commuter, '03 Fuji Roubaix Pro 853 back up training bike
    Posts
    701
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by lungimsam View Post
    I will try to look inside to see if the screws are contacting anything.
    One more possibility is that the threads in either the derailleur or the limit screws are stripped.
    "See, it's not that getting wet is a big deal. Really, it's what you're getting wet with.
    Fenders....because it's probably urine."
    Bike Snob NYC

Posting Permissions

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