chain rub in 53x11

Discussion in 'Cycling Equipment' started by jrstevens, Mar 20, 2006.

  1. jrstevens

    jrstevens New Member

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    I just recently switched from a compact carbon crankset to an Ultegra 53-39 external bearing setup. The LBS did the change. When I picked up the bike the mechanic noted that the chain rubs on the outside arm of the front derailleur when in 53x11 since the external design places the crank arms out further. I can't understand why this would be happening; I mean don't many bikes on the showroom floor have this setup. Any insight as to how to get this rectified would be appreciated.

    JS
     
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  2. alienator

    alienator Well-Known Member

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    This sounds like a load of crap. Check to see if your FD is aligned properly to the big chainring. If it is, then adjust the limit screw so the FD moves a bit away from the chainring.

    You should find a new mechanic.
     
  3. John M

    John M New Member

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    That is unacceptable. They probably have not set-up the front derailleur correctly. The proper steps to take are to disconnect the cable from the front derailleur and start over again with adjusting the front derailleur as if it were a new installation. See the Park tool website for detailed instructions. A standard Shimano FD should work with any double crankset-which by the way does not place the chainrings farther out.

    Check to make sure that they did not put spacers between the bottom bracket cups and the frame, which should not be required for 68mm BB road frames but are required for MTB external BB installations
     
  4. capwater

    capwater New Member

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    What a carpet smoking nose picker! Totally unacceptable to let the bike leave the shop with that issue. What's worse he tells you about it with a "hey, that's life" attitude. Schloads of folks riding external bearing cranks without chain rub. Five minutes work on that FD and any "competent" wrench should have it tweaked fine.
     
  5. jrstevens

    jrstevens New Member

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    so to complicate matters I get rub on the inside of the derailleur when I'm in 39x25!!!
     
  6. capwater

    capwater New Member

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    Not trying to insult your intelligence, but are you aware of the trim stop on a FD?
     
  7. jrstevens

    jrstevens New Member

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    I am aware but even using it in the extremes doesn't seem to stop the rub:(
     
  8. John M

    John M New Member

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    Like I suggested earlier, I think that the whole front derailleur set-up needs to redone, as if it were a new installation.

    The Park tool site will tell you the proper order to do things. If it starts out misaligned at an early step, further adjustments without fixing the first problem could just make things worse. This is something that you can try yourself before going back to the shop. If you do end up going back to them, you need a different mechanic from the one that did the installation to look at it.

    http://www.parktool.com/repair/readhowto.asp?id=75

    Interesting that you went from compact to 53/39 gearing. Seems that going compact is all the rage.
     
  9. gclark8

    gclark8 New Member

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    You may not have the correct Front Derailleur if you get rub on the 11 and 25 and you are using the trim feature.
    What model FD is fitted?

    Also I am curious as to why you would need to gear so high? 53-11 is huge, unless you are on 650c wheels.
     
  10. jrstevens

    jrstevens New Member

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    It's an Ultegra model, do they make separate FD's for external bearing cranks?

    53-11 comes in handy on descents here in Colorado and since I'm under 145# I need an extra gear to keep up with some of my heavier peers;)
     
  11. John M

    John M New Member

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    No. They make two Ultegra FDs, one for double cranks and another for triple. Both should work with your crankset. I am pretty sure that your problem is in the adjustment and not the component combination.
     
  12. TWOPBikeGuy

    TWOPBikeGuy New Member

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    I have noticed on some bikes the chain rubs on the 53 chainring itself, not the derailer, so check to make sure your BB spacing is correct as well.
     
  13. gclark8

    gclark8 New Member

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    OK.

    Its about the big ring diameter, the chainline will not change with different BBs. The Ultegra 10 double, FD-6600, will work from 50 to 56 teeth, so as long as it is the right one it is OK.

    Lets work through this systematically.

    Next, is the chain 10 speed?

    I am assuming the left shifter is Shimano ST-6600, Ultegra 10 speed double.

    Next, seat tube angle, is it steep, Time trial/Tri or shallower, a road frame?

    Next, chain stay length, is it over 405mm from BB centre to rear axle centre.

    My reference, Shimano 2006 Support Manual, page 192.
     
  14. jrstevens

    jrstevens New Member

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    FD for double crank

    10 spd chain

    correct shifter

    road frame, seat tube angle 74

    chain stay length 410mm
     
  15. gclark8

    gclark8 New Member

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    OK,all good. Now we go back to the comments in post #2,3, check the BB for spacers, is the chainline right? It should be 43.5mm. (not 45mm)
     
  16. jrstevens

    jrstevens New Member

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    what exactly is the chain line, sorry for being an ignoramus on that one
     
  17. gclark8

    gclark8 New Member

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  18. gclark8

    gclark8 New Member

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