Advertise on Bikeforums.net



User Tag List

Results 1 to 17 of 17
  1. #1
    Senior Member trek1's Avatar
    Join Date
    Mar 2006
    Location
    Novi, Michigan
    My Bikes
    Trek '06 2100ZR, 7.5FX, '05 Fuel EX8
    Posts
    459
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Chain coming off?

    I don't see what the problem could be to make my chain come off the front big ring (small raer) gear when going full speed. This had occured when I first bought my 2100 and my LBS showed me how the front derailuer was pushing the chain over and would then be the cause. Since this was corrected and looke to be in alignment, I just wonder what else I could be missing on but it is frustrating and I only have about 800 miles on it.
    Fuel EX8(05') 2100 ZR(06') 7.5 FX(06')=Best $ I ever spent =~)
    Mavic-Time-Sidi-PI-Primal-Giro-CamelBak-Bike Eye-Bell-Bandana-Park-eGel-PBJ's

    The bitter taste of poor quality far out lasts the sweet taste of a low price.

  2. #2
    Senior Member tbdean's Avatar
    Join Date
    Jun 2005
    Location
    Lawrenceville, GA
    Posts
    592
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Does it fall off immediately when you get to the big ring, or after riding for a while?

    While riding in the big ring, before it falls off, are you getting chain rub?

  3. #3
    Senior Member trek1's Avatar
    Join Date
    Mar 2006
    Location
    Novi, Michigan
    My Bikes
    Trek '06 2100ZR, 7.5FX, '05 Fuel EX8
    Posts
    459
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by tbdean
    Does it fall off immediately when you get to the big ring, or after riding for a while?

    While riding in the big ring, before it falls off, are you getting chain rub?
    No chain rub is noticeable and it was while I was shifting and once well after shifting that it will just roll off the outside. The 105 shifters have the 1/2 click but the alignment looks perfect up front. I am not sure if the rear alignmet is the culprit but nothing rubs and it is smooth otherwise. It doesn't leave you feeling comfortable when going say 30 MPH on my ride. It has been back to my LBS twice with this issue and they are good and the best in my area.
    Fuel EX8(05') 2100 ZR(06') 7.5 FX(06')=Best $ I ever spent =~)
    Mavic-Time-Sidi-PI-Primal-Giro-CamelBak-Bike Eye-Bell-Bandana-Park-eGel-PBJ's

    The bitter taste of poor quality far out lasts the sweet taste of a low price.

  4. #4
    Senior Member trek1's Avatar
    Join Date
    Mar 2006
    Location
    Novi, Michigan
    My Bikes
    Trek '06 2100ZR, 7.5FX, '05 Fuel EX8
    Posts
    459
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    it isn't rocket science I know, it's only mechanical but I wonder what is happening. It's almost like as the chain gains momentum it wants to fly off to the outside. Does anyone have any idea?
    Fuel EX8(05') 2100 ZR(06') 7.5 FX(06')=Best $ I ever spent =~)
    Mavic-Time-Sidi-PI-Primal-Giro-CamelBak-Bike Eye-Bell-Bandana-Park-eGel-PBJ's

    The bitter taste of poor quality far out lasts the sweet taste of a low price.

  5. #5
    Car free since 1995 pm124's Avatar
    Join Date
    Sep 2006
    Location
    NYC
    My Bikes
    Birdy Yellow, Birdy Monocoque
    Posts
    1,004
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Yes. This happens on folders all the time b/c the stays are shorter, because there is no front derailleur, and because you have to use all 9 rear gears on one ring. When you shift, it creates a wave in the chain, and this wave can whip the chain off of the front ring.

    Anyway, if the FD isn't preventing it from falling off, you should check to make sure that the ring is true. You should make sure that you aren't using extreme gears (e.g. using the big rear cog while on the big front cog). Finally, you should check your chainline. If it's falling off the outside, check the chainline from the high to high gears. Also, make sure your crank arm is bolted on tight. If all this fails, you might need to secure it (with an outter guard or a roller contraption http://www.gaerlan.com/dahon/gear.htm).

  6. #6
    Senior Member trek1's Avatar
    Join Date
    Mar 2006
    Location
    Novi, Michigan
    My Bikes
    Trek '06 2100ZR, 7.5FX, '05 Fuel EX8
    Posts
    459
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by pm124
    Anyway, if the FD isn't preventing it from falling off, you should check to make sure that the ring is true. You should make sure that you aren't using extreme gears (e.g. using the big rear cog while on the big front cog). Finally, you should check your chainline. If it's falling off the outside, check the chainline from the high to high gears. Also, make sure your crank arm is bolted on tight. If all this fails, you might need to secure it (with an outter guard or a roller contraption http://www.gaerlan.com/dahon/gear.htm).
    I really appreciate the suggestions you have posted, and I don't know enough about aligning the front derailuer. This happens only when the chain is not even crossed using the big front and small rear therefore in good tracking alignment. I was thinking that even if the LBS adjusted the limit screws to not force the chain over maybe it needs to be further restricted in the outer direction. Maybe it should not have the clearance to let the chain on the outside, I might try and see if I can get the outer face of the derailuer to be maybe 1/8" or so away. My LBS has also said again and it can be hard to duplicate some situations on the work stand without riding pressure and momentum happening.
    Fuel EX8(05') 2100 ZR(06') 7.5 FX(06')=Best $ I ever spent =~)
    Mavic-Time-Sidi-PI-Primal-Giro-CamelBak-Bike Eye-Bell-Bandana-Park-eGel-PBJ's

    The bitter taste of poor quality far out lasts the sweet taste of a low price.

  7. #7
    Don't call me sir cmdr's Avatar
    Join Date
    Jun 2006
    Location
    Charlottesville, VA
    My Bikes
    1954 Holdsworth 3 speed, 1969 Bob Jackson, 1988 Miyata Twelve Hundred (retired), 1989 Schwinn Paramount, 2004 Santa Cruz Blur Classic, 2012 Specialized P3, 2013 Specialized Roubaix Expert Disc
    Posts
    616
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    How big is the gap between the front derailleur and the large chainring? Maybe there is too large of a gap and the chain is sliding out between the two components.
    1969 Bob Jackson, 1989 Schwinn Paramount, 2004 Santa Cruz Blur, 2011 Specialized P-3, 2013 Salsa Colossal Ti

  8. #8
    B.C. to D.C.
    Join Date
    Oct 2005
    Location
    between the Popeye's, the liquor store, the funeral home, and the strip club
    My Bikes
    1992 Miyata Nine 14; 1971 Raleigh Super Course fixie conversion; 2006 Jamis Nova (853 version); 2001 Diamondback Topanga (SS conversion); 1956 Rudge Sports; 1971 Raleigh Competition (processing); 199? Schwinn World Sport (processing)
    Posts
    576
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    a couple of questions:

    a) what crankset are you using? I'm assuming 105 front and rear ders? 8,9, or 10 speed?

    b) is this happening regardless of the force applied to the pedals, or only under heavy torque?

  9. #9
    Senior Member
    Join Date
    Feb 2005
    Location
    Oklahoma
    My Bikes
    Trek 5500, Colnago C-50
    Posts
    9,096
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Since it's a new bike, make the LBS fix it. This should not be happening.
    Check for a tight link in the chain. Work each link with your fingers to see if the side plates rotate about the link pins freely. It's common to have a tight link where the chain was joined.
    It could be a poor chainline, if so it may be corrected with a thin bottom bracket spacer.

    Al

  10. #10
    Senior Member trek1's Avatar
    Join Date
    Mar 2006
    Location
    Novi, Michigan
    My Bikes
    Trek '06 2100ZR, 7.5FX, '05 Fuel EX8
    Posts
    459
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by cmdr
    How big is the gap between the front derailleur and the large chainring? Maybe there is too large of a gap and the chain is sliding out between the two components.
    It looks to be the width of a chain link but centered properly-still might need to limit it more.

    Quote Originally Posted by comradehoser
    a couple of questions:

    a) what crankset are you using? I'm assuming 105 front and rear ders? 8,9, or 10 speed?

    b) is this happening regardless of the force applied to the pedals, or only under heavy torque?
    a) 105 10 speed

    b) I believe so it happens all of a sudden but when going full speed down hill.

    Quote Originally Posted by Al1943
    Since it's a new bike, make the LBS fix it. This should not be happening.
    Check for a tight link in the chain. Work each link with your fingers to see if the side plates rotate about the link pins freely. It's common to have a tight link where the chain was joined.
    It could be a poor chainline, if so it may be corrected with a thin bottom bracket spacer.

    Al
    I like the quik link check and agree with let them fix it but they seem to think they are fixing it then it happens again
    Fuel EX8(05') 2100 ZR(06') 7.5 FX(06')=Best $ I ever spent =~)
    Mavic-Time-Sidi-PI-Primal-Giro-CamelBak-Bike Eye-Bell-Bandana-Park-eGel-PBJ's

    The bitter taste of poor quality far out lasts the sweet taste of a low price.

  11. #11
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by trek1
    It looks to be the width of a chain link but centered properly-still might need to limit it more.
    That sounds like a severly out-of-adjustment front-derailleur. There should be only 1-3mm of gap between the FD cage and chainring-teeth:



    Go to the Park Tool - Front Derailleur Adjustments repair section on how to set up and adjust a front-derailleur. The FD must be physically positioned and rotated correctly first before you can even make any other adjustment with the limit-screws or cable-tension.

  12. #12
    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
    6,938
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    An easy check for a stiff link is to slowly rotate the crank backward and observe the "jockey" pulleys on the Rder. When a stiff link passes through them, they'll "jump" to some extent.

  13. #13
    Senior Member trek1's Avatar
    Join Date
    Mar 2006
    Location
    Novi, Michigan
    My Bikes
    Trek '06 2100ZR, 7.5FX, '05 Fuel EX8
    Posts
    459
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DannoXYZ
    That sounds like a severly out-of-adjustment front-derailleur. There should be only 1-3mm of gap between the FD cage and chainring-teeth:


    Ah yes, it might be vertical as well in the adjustment, something is causing it to be able to jump off.

    Quote Originally Posted by Bill Kapaun
    An easy check for a stiff link is to slowly rotate the crank backward and observe the "jockey" pulleys on the Rder. When a stiff link passes through them, they'll "jump" to some extent.
    I will be looking into it this evening some more and thanks to everyone.
    Fuel EX8(05') 2100 ZR(06') 7.5 FX(06')=Best $ I ever spent =~)
    Mavic-Time-Sidi-PI-Primal-Giro-CamelBak-Bike Eye-Bell-Bandana-Park-eGel-PBJ's

    The bitter taste of poor quality far out lasts the sweet taste of a low price.

  14. #14
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by trek1
    Ah yes, it might be vertical as well in the adjustment, something is causing it to be able to jump off.
    What happens when the FD is too high vertically is that you must move it outward laterally an excessive amount to get the chain to go from small to big-chainring. This extra lateral movement can be an extra 3-5mm. This leaves more than enough space for the ring to fall off the outside if you hit a bump or something. The adjustment steps for a FD is roughly as follows:

    1. adjust vertical so outer-cage is 1-3mm above big-chainring teeth (cage in same plane as big-ring).
    2. adjust lateral rotation so outer-cage is parallel with chain in largest gear (not parallel with big-ring as most shops do).
    3. tighten down FD clamp
    4. adjust cable tension for optimum up & down shifting
    5. adjust limit screws

  15. #15
    Senior Member trek1's Avatar
    Join Date
    Mar 2006
    Location
    Novi, Michigan
    My Bikes
    Trek '06 2100ZR, 7.5FX, '05 Fuel EX8
    Posts
    459
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I don't know? Everything looks to be in alignmet (see pics). I don't know about the 2 teeth that are flattened down if you look close in the side view but my XC bike has more wear than them and the chain never comes off that bike.
    Attached Images Attached Images
    Fuel EX8(05') 2100 ZR(06') 7.5 FX(06')=Best $ I ever spent =~)
    Mavic-Time-Sidi-PI-Primal-Giro-CamelBak-Bike Eye-Bell-Bandana-Park-eGel-PBJ's

    The bitter taste of poor quality far out lasts the sweet taste of a low price.

  16. #16
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,495
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by trek1
    I don't know? Everything looks to be in alignmet (see pics). I don't know about the 2 teeth that are flattened down if you look close in the side view but my XC bike has more wear than them and the chain never comes off that bike.
    The vertical and rotation adjustment seems about right. Is the FD shifted all the way out? Can't see where there's room for the chain to slip out between the chainring & FD.

    Put the bike into the small ring and spin the crank backwards. Look down at the FD & chainring. Using the outer cage as a guide, does the chainring stay straight? It doesn't wobble in & out?

  17. #17
    Senior Member
    Join Date
    Sep 2001
    Location
    Montreal
    My Bikes
    Peugeot Hybrid, Minelli Hybrid
    Posts
    6,521
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Is the freehub sticking? If you have the bike on the stand, turn the pedals to get the wheel moving fast then stop the pedals. Does the wheel drive the pedals around. A sticky freewheel mechanism might be pushing the chain forward when you are going fast downhill allowing it to flap up and down. This is a crazy thought but easy enough to check.

Posting Permissions

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